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Elite Veteran
 
Location: Medford, OR | So I took FMC #850 out for a family cruise last weekend over to the in-laws house for a bbq, maybe an 8 mile round trip is all, 75-80 degree Spring day. It was my girlfriend and my daughters first time riding in it (I've been working on 850 in the driveway for the last two years!) They both loved sitting in the front seat looking out at the world. It's a completely different experience driving and riding in an FMC coach then a standard class A motorhome. We stopped at the gas station and I put 25.00 of non-ethanol fuel in it for kicks. Everything was working great, the only issue I was feeling was a mild flat/dead spot on acceleration from a stop, and at times it would not build rpms real fast with the throttle hammered. Like the 440 was a little loaded up?, OR was it running too lean?? (These were thoughts that were running through my head at the time). It could be caused by multiple things, I will dive into that after I fix my vapor lock/fuel starved issue. Anyway, upon leaving the In-laws bbq, after showing off the rig, and getting ohh's and ahh's. We loaded back up. As I was getting in and about to start 850 up, I happily said to Kt, "I'm really feeling good and confident about the old FMC", (After all, I just got done with ALL the mechanical maintenance you can almost do to a motorhome's running gear!!!) So we headed out, got about two miles down the road, then bam! 850 starts obviously starving for fuel, luckily I was able to nurse the throttle through a few lonnngggg stale green stop lights that we got lucky on, and didn't have to stop before turning onto the old back streets of neighborhood that we live in. So as I still nurse the throttle, I see my house is in sight! Going to make it to the driveway! Nope! Died flat on her a$$ one block from the house. I put on the four ways, ran to the back and opened her up, first thing I did was unscrew the fuel filter canister and found only a table spoon on the bottom (should of been full of fuel), and the filter looked like new still. I put the filter back together quickly, took the air filter housing loose on top of the carb (Thermoquad) and pumped the throttle by hand to listen for fuel. I didn't hear any fuel spraying, so I pumped it maybe ten times then I heard fuel spraying!! yay! Closed the rear doors, run to the front and she fired right up! Kt looked at me and said, "Damn, you are good?" I laughed hahaha.
In my history with a manual fuel pump motor vapor locking, I've never been able to get them started back up and running "on there own" until they cool off, like 30 minutes. 850 was only shut down/out of service/capput for 1-2 minutes in the middle of the road. So by me opening the fuel filter before the manual pump release pressure? Or? Why would the carb start pumping fuel again? Where did the fuel come from? Kinda weird.
What I did different with the fuel system before this "Sunday Drive", was I installed a 3-port fuel filter "after" the manual pump, 5/16" in and out, 1/4" vapor port to return to tank (I read that this style of system prevents vapor lock) I didn't have my new vented fuel cap arrive in the mail yet, so I left the old factory gas cap loose so the tank would vent. Even with the original straight fuel line from the pump to the carb, I think it would have still vapor locked, but who knows, this was the warmest temp day I've driven it so far.
The fuel pump that is on the 440 is old, I don't know what pressure it's pushing either, I need to go pick up an inline gauge and check. But in my history trying to stop vapor lock situations, replacing the manual pump never solved it. So I need to just go electric. I want to run the best pump available, should I buy the Red Holley and regulator? Or?? We have a Red Holley on our 1986 P30 rig, it's been working well, but kinda loud, the P30 also has a built in fuel return system in the manual pump. The 440 does not, that pump will have to go, and put a fuel pump block off plate on.
Which electric fuel pumps and regulators do you run? And at what pressure is your Thermoquad happy at?
Thank you,
Dan #850
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Extreme Veteran
Location: Scottsdale, Aridzona | 3 Port filter that prevents vapor lock ? Mechanical pumps and fuel lines that run past very hot exhaust manifolds have vapor locked since Henry Ford started all this.
But a small VAPOR bleed (?) is going to stop vapor lock ? Why do you have VAPOR in the fuel line between the mechanical pump and the Carb ?
Used this pump in everything since Auto Shop in High School . . . with a regular Fram fuel filter before the pump.
http://www.summitracing.com/parts/crt-p4602rv/overview/
Gas ON ! Lou #120
Edited by hemi354az 2016-05-02 1:48 PM
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Elite Veteran
Location: Medford, OR | That is the pump that used to be in 850 Lou, the 3 stud mounting style. Thank you. That mounting bracket is already installed beside the radiator from a previous owner, someone stole it for a different project I guess......sweet.
I read that adding the 1/4" vapor port filter between the pump and carb keeps the fuel moving? I guess not! ha |
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Elite Veteran
Location: Medford, OR | Should I run a regulator with this pump? |
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Extreme Veteran
Location: Ignacio Colorado | I think you still need to fix the problem! Vapor lock is caused when the fuel boils before the pump in most cases. You only drove 8 miles, hot soaked it then started back for home. First get rid of the 3 way filter after stock pump and go back to the 2 port filter. Look at the rubber fuel line from the top of tank to the steel line going towards fuel pump and all other rubber fuel hose before the pump. If you have not replaced them it would be a good time to do so. A small crack on the very top is all it takes, plus now some of your pumped fuel is going back to the tank. Remove return line and replace the supply lines before you condemn your pump. Bill |
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Elite Veteran
Location: Medford, OR | All my rubber lines have been replaced within the last 2 years. The rubber line just before the "in" port on the pump runs within 5-6" from the rear port of the exhaust manifold, that would probably be a good spot for vapor lock issues. My steel lines running along the frame from the tank back to the filter (filter is mounted on the side of the radiator), that line runs above the duel exhaust system also. The previous owner wrapped different styles of rubber line and black tape around this steel line also? Looks like crap.
I am going to check fuel pressure in the next day or so...I will remove the 3-port filter and go back to the stock set-up. |
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Extreme Veteran
Location: Ignacio Colorado | I am amazed how fast fuel lines deteriorate with todays fuels. I replaced the line from the tank 3 years back. Tried to fire it up for spring over the weekend but it never fired. It was late and then yesterday it snowed like crazy. I'll bet my line is already cracked. Time is short as we plan to take it to the lake this weekend. Bill |
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Extreme Veteran
Location: Scottsdale, Aridzona | Regulator ? Regulators are for HOT ROD RACE CARS that have very high fuel flow at big RPM numbers. I know this is hard . . . A FMC 2900R is NOT a race car.
If you choose the Carter 4602 electric fuel pump you can run it safely without any regulator. Don't know about mounting it to the radiator, and tape and other stuff.
Mechanical fuel pumps that vapor locked got Genuine Reynolds Aluminum Foil on the metal fuel line . . . if you were a rich kid. The rest of us used wooden clothes pins.
You have the good low exhaust manifolds. Why not mount it on the firewall where the fuel hose comes out of the firewall, and run the line straight over to the engine, along the inside of the valve cover to the rear gas line hook up on the T-Quad carb. I like steel braided/rubber/teflon lined Aeroquip hose and fittings for fuel line. Gas ON ! Lou #120
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Elite Veteran
Location: Medford, OR | If I end up going with the electric pump, I was definitely planning on mounting it on the firewall etc..and loose some sweet tape. |
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Elite Veteran
Location: Medford, OR | Ok! Conclusion! So not everything you read on the web is true? Ha. The 3-port filter screwed me. I put a fuel pressure gauge on it, 0-3 pounds, crimp the 3rd port vapor line, and I have a solid 7 pounds out of the old mechanical pump. So I will be putting it back to stock, then I will carry a spare mechanical pump in the rig if ever needed...Thanks for helping me fix my dumb decisions
Dan
#850 |
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Elite Veteran
Location: Medford, OR | Well...just took 850 out for a cruise with the new meats. Handled great! Good news for that unknown. Filled the fuel tank, then hit the highway....45-50 mph she runs out of fuel! Back off the throttle and cruise on the shoulder about 40 mph and she holds strong. I'm going to call this a "volume" issue. It runs great around town stop light to stop light, and it's hot here today too. The water temp stayed between 180-190. The fuel pump is the same mechanical pump that's been on it for ump-teen years....So do I bite the bullet and buy the Carter electric pump and all the associated bs to install? Or do I buy a new quality mechanical pump and give her a shot??? What do you super FMC experienced gents think.....
Dan
#850 |
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Veteran
Location: Olympia, Washington | You might want to test the pressure, the volume and the suction of the existing fuel pump to determine if it is good or bad. Had a bad coil, wire once darned if it didn't act like it was running out of gas. |
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Elite Veteran
Location: Medford, OR | Pressure was close to 7 at idle. The only time it has issues is on a hard pull, like a freeway on ramp. Runs out of steam. I think if it were coil issue, I would have a more reacureing issue all over the board?? Idk |
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Elite Veteran
Location: Oceanside, CA | You sure you don't have a carb float level issue? Not keeping enough fuel in the bowl?
Also could be an ignition advance problem, bad/no vacuum advance while loading at speed would make it feel like it has no power.
Be sure your choke is fully opening as well. |
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Veteran
Location: Olympia, Washington | All I'm saying is in my case what seemed like a fuel problem was actually an ignition problem. Test don't guess if you suspect lack of fuel figure out a way to add more fuel. If the engine picks up with enrichment you have proven that lack of fuel is the problem. Now you must find out why the engine lacks fuel. If it does not respond to enrichment it's time to look somewhere else for the problem. |
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Elite Veteran
Location: Medford, OR | I need more fuel like you said George...I rebuilt the Thermoquad and adjusted per spec. And used a vacuum gauge to fine tune. Choke is good. Distributor advance worked fine last time I manually checked it. I'm not lacking power, just running out of fuel after an 1/8 mile hard pull then everything goes flat until I back off the pedal and cruise at a slower speed. I may look into an Edelbrock pump? Idk. Fuel line is 3/8 to the pump, 5/16 to the carb. I'm not sure how to do a volume test other than put the hose in a bucket and keep the motor running with some fuel out of a bottle? Is there a gallon per minute number or something I need to shoot for?? Thanks for the ideas guys |
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Extreme Veteran
Location: Scottsdale, Aridzona | I (and lots of my Hot Rod friends) have had good reliable service with this one - https://www.summitracing.com/parts/crt-p4594/overview/
Pump ON ! Lou #120 |
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Elite Veteran
Location: Medford, OR | Ok. I need one pint in 30 seconds or less. I'll check that first, then on to the other. |
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Elite Veteran
Location: Medford, OR | Ok, just did the volume test: 1/2 pint of fuel with engine idling for 30 seconds. I think my fuel pump loses. All hoses and the fuel filter itself before the pump are great. |
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Contributor
| #850, I have experienced this before in the past in a truck from the same era. It is possible the problem is in the fuel tank, namely the fuel sender unit getting clogged. I have not seen a picture or line art drawing of the sending units FMC used, but rust scale could be clogging the fuel sock (a fine fabric mesh screen) located on the end of the pickup tube in the sending unit assembly or clogging the pickup tube itself if a fuel sock is not used. You start and drive down the road just fine and after a few miles your engine starts starving for fuel. You stop, and after awhile the rust scale/particles settles down and falls away from the fuel sock and/or tube; You start up and everything is fine again until the agitation in the fuel tank stirs up the scale, clogs the sock filter and/or pickup tube yet again and the engine is starved of fuel once more. I would check the sending unit and inspect the interior of the fuel tank.
(Just an FYI, Duramaxer's FMCMotorcoach.com manuals page is missing a page in the fuel section, removal of the fuel sending unit - page 11-16. I checked my hard copy manual and the directions for removal and installation of the fuel tank sending unit are there on page 11-16 but no drawing of the sending unit).
Edited by TX-FMC 2016-08-06 10:23 PM
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Extreme Veteran
Location: Scottsdale, Aridzona | No socks (or shoes, or coverings of any kind) appear in the in tank fuel pickup in the FMC PARTS BOOK Group 11 . . . of that era.
Dance ON ! Lou #120
Edited by hemi354az 2016-08-06 10:58 PM
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Extreme Veteran
Location: Ignacio Colorado | Hate to say it but I have seen the seats (needle and seat) back out and starve the TQ carb for fuel. If the pump does not solve the problem this is the next place to look. BTW what did you set the floats at? TQ? Bill |
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Elite Veteran
Location: Medford, OR | I can't remember off the top of my head forsure, but I believe I set the float level just shy of 1". I do have a slight weep on the air horn gasket at one corner. I am planning on removing it sometime and sanding the body a little, but it's really nothing that dust won't just catch....So I believe if I have fuel wanting to weep out up that high in the carb, I have a full bowl. Just my own theory. I already know a new fuel pump is going on hopefully tomorrow. I will fully test the new pump before driving. Tex, as much as I have ran this engine, I've never had accumulation of any kind trapped in the fuel filter. Like I said earlier (kind of), the only time I can make/or duplicate the issue I'm having, is if you lined up #850 next to.... say a GMC Palmbeach! For a quarter mile drag race, about half way down the track that's when 850 starts to shit......lol |
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Veteran
Location: Olympia, Washington | So the existing pump passed the pressure test but failed the volume test? 9 out of 10 cars it would be fine but alas our 440's are way to thirsty for that. Drives like a sports car and passes everything except a gas station. |
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Elite Veteran
Location: Victoria, BC. Canada | This is interesting and I'm looking forward to you finding the solution, Dan.
Terry
#846 |
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Contributor
| The fuel sock may not be listed as a separate part in the manual because it is usually sold as an integral part of the sending unit. Similar to needing a float for the thermoquad carburetor, the float by itself will not be listed in the FMC manual. (You would refer to a thermoquad manual pertaining to year make engine displacement, etc.). Below is a link to a generic Mopar sending unit. The off-white "cylinder" at the end of the pick up tube is the mesh fuel filter sock. If you want to replace only the fuel sock you may possibly be able to go to a auto parts store with the old one to match one up. The fuel sock is hard to get off the tube, extreme care is needed in order to not damage the rheostat float level electrical sending mechanism. The problem is probably not the sock, but the rust scales/particles in the tank - the tank will need to be flushed, and/or sealed or replaced. If you have to go into the tank it would be wise to just change out the whole sending unit while it is out.
http://www.521restorations.com/images/KEV/bsend38bnr.jpg
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Elite Veteran
Location: Medford, OR | Ive talked to everyone and their brother here in the valley, and not one parts store has a 440 fuel pump!! I ordered one, be here in two days. Crazy |
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Extreme Veteran
Location: Scottsdale, Aridzona | That is all very interesting TEX. There is a simple solution to every problem . . . and it is often wrong.
The FMC does NOT have a Chrysler fuel tank pickup/sender. As stated in the Parts Manual, it has a Snyder or VDO sender.
The FMC Parts Manual Illustrations are pretty damn good. No sock is shown . . . because there isn't one on a FMC.
Floats in the T-Quad carb are not shown either, as they are not a "service" item . . . but the Carb Assy Part Number is shown in the list so you can use other sources to find floats if you need them. That is pretty common "whole vehicle" Parts Books.
But . . . I happen to remember what I have seen right here on this website . . .
Fuel pickup/sender out of FMC #1027 - http://www.fmcowners.com/mbbs22/photos/show-album.asp?albumid=77&ph...
Fuel pickup/sender out of FMC #477 - http://www.fmcowners.com/mbbs22/photos/show-album.asp?albumid=14&ph...
There are lots of "socks" - https://www.google.com/search?q=Filter+socks+on+gas+tank+pickups+%3F...
I don't care for them, as they are hidden and difficult to determine if they are "clogged". I like in line fuel filters tho, as they can be cut apart to see if they were clogged, and if so, I use the drain plug on the gas tank (FMC has one, but many don't) to further "examine" what is in the tank, to determine what to do next about indicated "fuel contamination", or "plugged filter flow".
Oh well . . . DK still has a "unsolved" fuel/electrical/linkage problem.
Search ON, Lou #120
Edited by hemi354az 2016-08-07 1:17 PM
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Extreme Veteran
Location: Scottsdale, Aridzona | DK, if you are changing the mechanical fuel pump . . . take a look - http://www.fmcowners.com/mbbs22/photos/photo-thumbnails.asp?albumid...
Might save you some time and frustration getting the new one mounted.
Here is a Carter Part Number, M4589, NAPA #AFP6774, Airtex #6774, Delphi #MF01130, Spectra #SP1111MP or #SP1349MP, to give the Parts Counter Rocket Scientist to cross reference . . . or
https://www.summitracing.com/parts/crt-m4589?seid=srese1&cm_mmc=pla-...
Pump ON ! Lou #120
Edited by hemi354az 2016-08-07 1:16 PM
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Elite Veteran
Location: Medford, OR | Amazon had the Airtex pump. When I pulled #184's full sendor/pickup assembly out, looked the same as Lous pics. Tuesday night I will post my findings with the new pump.
Edited by dkarnath 2016-08-07 1:42 PM
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Contributor
| Wow, thanks for the pics hemi. This issue has been one of my fears for years - a rusty gas tank. I have serviced farm and industrial equipment that have had the same pick up tube design, a simple tube and float with no sock - they had fuel starvation issues related to rust scale clogging the pick up tube. After cleaning and/or changing the fuel tanks the problems were solved. This is just one possible issue that can be a cause. |
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Extreme Veteran
Location: Scottsdale, Aridzona | Hey TEX, check you Mail on this Website. Sent you a brief message. Lou #120
Edited by hemi354az 2016-08-07 2:11 PM
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Contributor
| Lou's picture process on this is worth a thousand words. When servicing a 440 fuel pump and the pushrod had slid down, if grease doesn't hold it in long enough I have removed the pipe plug in order to insert a thin rod or something of the sort through the plug hole to push the rod back and hold it into its shaft while inserting the fuel pump arm in front of the rod in order to be sure it is installed properly. If the bolts start getting tight and there is still a significant gap between the pump mounting face and the block while bolting the fuel pump on - stop. The fuel pump arm is probably not in front of the rod but resting on top of it. Lou is right in that you have maybe only a few chances to get that plug out successfully - it has been in there for forty years. Make sure there is no debris in the plug head pocket and the tool to remove it is inserted all the way - preferably using a proper sized bit on an air impact wrench. (I have done it with a 90 degree wrench before but you have to exert lots of pressure inward and at the right angle of the plug - both consistently and that the force is at best precisely to the right angle of the plug. Otherwise you will wallow out the socket hole. (The only way to remove it at that point is to drill it and use an "easy out" to get the rest of it out, not fun).
[Just an FYI: on Chevrolet 350's of the same era there is a bolt on the front face of the block that you can remove. Push the pump rod in, then lightly tighten a longer bolt through the same hole of the bolt you took out on the front of the block - the longer bolt will "bottom out" on the side of the pump rod and hold it in for you. Once the pump is installed remove the long bolt and put the original short bolt back in]. |
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Elite Veteran
Location: Medford, OR | So I picked up the new fuel pump today. It was nice to see that it has a 3/8 inlet, my old pump was 5/16. #850 has 3/8 from the tank to the inline fuel filter, 5/16 from the filter to the pump (about 2' worth), then 5/16 line to the TQ. The new pump is installed, but I had to go buy a 90% 3/8's fitting and some fuel line to complete the 3/8 line. It'll be fired up tomorrow. |
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Elite Veteran
Location: Medford, OR |
Yesterday was the perfect 100 degree day to take it for a drive..... :-[ . Ran great from stop light to stop light, Ran great on the 40 mph four lane hwy hammering the throttle down, then it ran great on the 50 mph four lane hwy hammering the throttle down from time to time picking up speed. I'm now about 7-8 miles away from home where I decided to take Interstate I-5 back to the house. It ran like $hit as soon as I merged into traffic on the Interstate!!! Same scenario as described earlier in this thread (pulls hard until about 50 mph). It seems as though when the ambient or "under hood" temps get to a certain temp, It starts vapor locking...So I took it easy and drove it home, runs great at slow speeds! FMC's pack some serious heat in the engine compartment!! I couldn't even touch the rear bumper it was so hot! I opened the rear access hatch to the engine (barely) lol, and touched the fuel supply line before the pump, and it was smoking hot, even with the fuel tank in front of the engine behind the fire wall, the fuel supply line was hotter than hell, that doesn't help with vapor lock issues....So I'm going to check the supply line for any resistance (like the fuel tank pick up assembly), and if all is good there, I will order a Carter 4070 electric pump and install and then get rid of the mechanical pump....I'm trying to make it to Oakridge boys! I've already had TWO flat tires (sitting in the driveway) because of faulty Ebay inner tubes.....I have extra tubes/air to bring with me for the Oakridge trip....Still looking for that spare tire....lol |
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Veteran
Location: Soquel, CA. | I gotta say, even though these beasts do indeed run hot back there, and I have run mine through 100 degree deserts up grades, your description of just how hot yours is getting, particularly the fuel line, seems a tad extreme. I feel like there is something else going on here too. At the very least, not enough protection of the fuel line (and filter?) from the exhaust system, which is likely running directly below, right? I guess I am going to need to check for that on mine specifically, on the next drive. But, I often have to stick my head in there through the back to get to the transmission dipstick with the engine hot after driving and running. Yes, it is hot in there, but do-able. Sounds like yours is not so much, which gives me pause. |
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Expert
Location: Cottage Grove, OR | I kind of agree with Greg. What you are describing seems hotter than what my experience has been. Have you correctly oriented the fan with the concave side to the rear/radiator side? Is the fan 2/3 of the way inside of the fan shroud? |
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Elite Veteran
Location: Medford, OR | That's funny you mentioned checking the tranny fluid, because that was what I was doing when I first got back to the house and noticed the high heat (I just resealed the speedometer gear housing earlier in the day). My water temp never got higher than 195 on the gauge. (Smoking hot) may of not been the correct term for the fuel line.... It was hot though just like everything else. I should have pulled out the infrared gun.... |
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Elite Veteran
Location: Victoria, BC. Canada | Hey Dan I just got back from a short run to Vancouver and back on the weekend and also experienced what seems to be vapor-lock. Mine would start bogging shortly after starting off from a standstill; after about 50yds or less it would begin to stumble (missing?) for about another 100 yds or so then it would settle down and be good then on upwards. Only happening shortly after start off. The only day it was doing it was hotter than the rest (90 degrees or higher) and I couldn't get it to do it again later that same day with my brother-in-law (a mechanic) on board. So, I'm going to buy some insulated foil tape and wrap all visible fuel lines I can get at and hope that does the trick.
Terry
#846 |
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Elite Veteran
Location: Medford, OR | Ill check the fan Stephen, I'm pretty sure it's correct, but I will look when I get home. Our "Rogue Valley" gas isn't the greatest. We are at the end of the fuel delivery line, and when I take a rig out of town, I ALWAYS get better mileage running off other areas fuel...It takes a tank of fuel (basically) in out other motorhome to drive to WA state. When I come back home after filling in WA, I have just under a half tank?? Explain that? This has happened on many different trips with many different vehicles. There is actually people talking about it on the web...Anyway, back to fuel fun. |
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Veteran
Location: Oslo Norway | Have you checked the fuel pick up yet?
A damaged fuel pick up could give you some very strange and inconsistent symptoms from variables like fuel tank level, acceleration, deceleration, up & down hill and outside temperature.
Try to diagnose this problem without running your engine out of fuel more than necessary, the repeated "starving" could put a lot of unnecessary wear on the old thing.
Kjetil
#477
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Elite Veteran
Location: Medford, OR | I blew through the supply line last night Kjetil, no restrictions. For the last 2.5 years, I've only averaged 1/4-1/3 tank of fuel, I just filled it completely a month ago. I know the pickup is pulling fuel out of the tank just fine, I don't see the need to pull the assembly completely out at this point. I'm going to remove the TQ tonight and inspect. Hopefully I find a piece of garbage in it, or maybe the secondary's are sticking?? We'll see... |
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Elite Veteran
Location: Medford, OR | I pulled the TQ off last night, I found nothing unusual about it. It blew freely through the needle and seat, I was able to get a 1/4 turn on all the body screws though. So I'm glad I took another look at it after the rebuild. I posted pics in my album showing the supply fuel line and the "old" carter electric pump mount. |
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Elite Veteran
Location: Medford, OR | Well.....I installed the electric pump and relocated the fuel supply lines further away from the exhaust. The pump puts out 6.5 pounds pressure. The spark plugs i looked at are showing lean burn vs rich. Took it for a drive and as soon as I hit the highway!!!! BAM still have the same issues! It actually runs worse with the new pump. I had to nurse her home around 25 mph's. I pulled the coil and it checks out good on the specs (I even compared it to three other coils at the part store), I also checked the resistance specs for the pick-up coil in the dizzy = good. So I am going to tear into the Thermoquad I guess... |
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Expert
Location: Cottage Grove, OR | Dang!! |
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Elite Veteran
Location: Medford, OR | Yeah it's been awhile since I have been this stumped on an engine, maybe I've been stubborn about my carb rebuild? Lol. That's where I'm goin next....time to clean the tools off the bench.
Edited by dkarnath 2016-09-10 10:09 PM
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Veteran
Location: Bethune, SC | I have a boxed, ready-to-ship rebuilt Thermoquad. It was built by a nationally known Thermoquad rebuilder in Atlanta for a 440 motor home engine. A friend suggested I use another carb I had on the shelf that would be much better so I installed it. This carb has been in a climate controlled environment for the last 8 years. It's yours, including shipping, for $175. The only warranty I will make is that you will get a rebuilt Thermoquad. The price is about half what I paid for the rebuild. I will ship the carb USPS Priority so you should have it by Wednesday or Thursday. Henry |
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Elite Veteran
Location: Victoria, BC. Canada | What great guy Henry! You can sit by my campfire ANYTIME!
Terry
#846 |
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Elite Veteran
Location: Medford, OR | Thanks Henry! The rebuild kits are about 50 bucks themselves now. Let me sleep on it for a few days. I just got the bench cleaned up, going to pull the TQ maybe tonight...well maybe not, it's 10 o'clock now. |
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Extreme Veteran
Location: Ignacio Colorado | The fact it is getting worse brings me back to the carter AVS I had acting the same way. The needle seats were backing out and effectively dropping the float level and causing fuel starvation.
Some TQ carbs have a screen filter inside the fitting the fuel line attaches to. Look at that fitting first.
The engine does recover if you get out of the throttle right? Runs ok then falls on it's face again when you get back into it? If so forget any electrical issues. Only chase one tail, the ghost tails you start chasing will branch out and lead you away from the real issue. If it quacks like a duck hunt duck.
Bill |
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Elite Veteran
Location: Medford, OR | Carb is on the bench, hopefully look inside today!! |
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Elite Veteran
Location: Medford, OR | Here's what I found with the TQ:
Everything looks great! Except for my float bowl adjustment from a couple years ago....I bent the "tang" that touches/closes the needle in order to set the correct 1" float height. Doing some homework today, a Thermoquads floats are adjusted by bending the float arm itself. I didn't know that. SO....now I need to figure out the correct position of the needle shut off metal tang, then adjust the float height. Reading info online hasn't quite answered this question completely...some say the float should almost touch the air horn body (in the closed position),then adjust the float...But when the float assembly is down to where it almost touches the body, it puts the needle/float tang at a crazy angle? It still shuts off fuel flow, but looks like its pushing the needle to the side vs straight in on it? Is this making any sense to anyone? Lol. Nobody really talks about "needle drop specs" to much. |
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Extreme Veteran
Location: Ignacio Colorado | Time to get a new set of floats. Unless they are brass I replace TQ floats every rebuild. Float drop is what the spec for full open is called. You don't want the floats to rest on the bottom of the bowl. Also too much drop may cause needle to bind as fuel level rises. I know the 1" float setting is not the spec but if you want a TQ to run without problems 1" is the best level I have found. Be sure nothing is stuck in the carb upside of the seats.
Bill |
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Elite Veteran
Location: Medford, OR | They are plastic. I can order a set of brass for about 25.00.
I wonder if this could be the reason 850 was parked 20 years ago? Of course, I probably messed the floats up myself, but the TQ choke system was all froze up when I drove it home, I couldn't get full throttle at that time, so who knows....I often think about that...why was it parked. Hmm
This whole thing just p's me off. Two fuel systems = fail. Now mystery float issues = fail. Well, even if a new set of brass floats fixes it, I'm not even sure what "fuel system" I should run?? Electric, or mechanical?? Hell, I have both! I love wasting my time. Not sure about making Oakridge, with a 19 month old daughter running around, I get minimal FMC time, right now I still only have a really expensive tent, that won't push itself down the hwy.......#850 might make it to Craigslist?.....haha! Ok, done ranting.
Edited by dkarnath 2016-09-12 11:59 AM
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Extreme Veteran
Location: Ignacio Colorado | The choke and secondary air valve are somewhat intertwined. A (the right) choke problem can have adverse affects on secondary air valve opening. Even wrong vacuum port routing to the choke pull off affects secondary opening. I don't see this causing the present issue.
Just thinking... Is the metering rod piston/holding fixture free moving and spring loaded to top of carb? If the piston is seized down the rods will not rise to allow the fuel mixture to go rich causing starvation. Also be sure the rods are attached to the fixture and not dropped down. If they are not removed before the top is removed getting them back in right is no easy feat.
The small rubber seals in fuel bowl that seal secondary main wells to top of carb get missed and cause major flooding so watch for them.
Bill |
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Elite Veteran
Location: Medford, OR | The metering rods/piston move freely up and down. I believe if that assembly was stuck/seized down, you wouldn't be able to get full throttle due to the step up linkage. I found this out on my first TQ that I tore apart! And yes, I also found out you have to remove the metering rods etc first before trying to take the air horn body off, vice versa. lol
I was wondering about the choke pull off. I know that it holds vacuum, but whether or not it drops off fast enough for the secondary air valve door to open, I don't know? Can't see it work back there!! The secondary door's spring feels good, no binding, snaps back nice to the closed position. I could actually adjust the closed door postition to be tighter, the spec is .040", I have probably .060". A lot of people set this .040" measurement to "0" I guess. I have no bog between the primary's and secondary's. To be honest I don't remember even feeling/hearing a difference between the two, other than my foot down on the floor...
I'm going to modify my floats and put it back together and see what happens. |
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Elite Veteran
Location: Medford, OR | I just ordered brass floats and a new needle and seat. One of the needles were sticking in the closed position fairly easily, had grooves. This "should" be my fix!! |
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Elite Veteran
Location: Medford, OR | I put the new brass floats in and have smooth working needles.....BUT same issues. Pulls hard until 40 mph or so, then starts falling on its face. Brought her home and pulled the tank pick-up out, I thought maybe I'd see a pin hole or something up high, but no, looks to be in excellent condition. I think I need a new carburetor. I'm out of trouble shooting options as far as I'm concerned.... |
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Extreme Veteran
Location: Ignacio Colorado | Be sure fuel pickup is not touching the tank floor if it is a straight tube. Did you remove the fuel inlet fitting on carb to check for a filter? Clamp some fuel line on line that attaches to carb and run electric pump with that hose in 5 gallon gas can and be sure flow is good and steady. Can't see it being a fatal carb problem. Pulling hard until 40 is the tough part I still think supply to carb or restriction in carb that has to be something between fuel supply fitting and needle and seats. Nothing there is hard to blow out. Hidden filter?? or big chunk of crud?? I have seen both. Good luck.
Bill |
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Elite Veteran
Location: Medford, OR | FIXED!!!!!!! BILL you ass! You talked earlier about sucking air??? Today with help from the father in law, we tied in some clear tubing along with the fuel pressure gauge and taped it to the back window. I drove the rig while the other person watched the gauge from the back bedroom. Fuel pressure would drop to ZERO under hard acceleration, along with AIR BUBBLES running through the line!!! I bypassed the supply line from the tank, still had air bubbles, I then bypassed the fuel filter....BAM!! The fuel filter assembly was sucking air...needless to say, I'm not going to use that old filter. Took it for another drive and she ran flawlessly down the highway maintaining 6 psi with no air being introduced into the system. I will post pics of the funky gauge set up. Thanks Bill for giving me (more than one time) the correct fix on this situation. I wish I would have done this bypass of the fuel supply system earlier. I am a happy man.
Dan
#850 |
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Elite Veteran
Location: Medford, OR | Yes we are planning on Oakridge!! |
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Elite Veteran
Location: Victoria, BC. Canada | Good-ass Billy they call him!
Way to go Dan.
Look forward to meeting you guys.
...if my tranny holds up.
Terry
#846 |
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Elite Veteran
Location: Medford, OR | After I parked 850 in the driveway.... Me and the father in law were celebrating with an ICE COLD beer, I looked at 850 and noticed the front tire was flat!!!! Another faulty tube gone boom. Hopefully my tires hold out Terry!! |
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Elite Veteran
Location: Victoria, BC. Canada | Find some Alcoa's or 19.5" steelie's.
Worth the expense if you plan to keep her... till your broke!
Ha-ha!
Terry
#846 |
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Elite Veteran
Location: Medford, OR | Yeah thanks Terry....OR I pull the rest of my balding spot hair out!! Ha |
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Expert
Location: Cottage Grove, OR | dkarnath - 2016-09-18 6:49 PM Yes we are planning on Oakridge!!
Great! I knew you could do it! We will see you in Oakridge. |
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Extreme Veteran
Location: Ignacio Colorado | "FIXED!!!!!!! BILL you ass! " Why does it always end that way? Back in my Chrysler dealer tech days, I stopped by one of the other tech's bay to find wires all over the place, new car torn half way apart trying to find out why the radio would not work. He had been at it for some time. I looked under the hood and plugged in the I.O.D. (ignition off draw) connecter and all was well with the world. Talk about pissed off. Hey not my fault, ask first next time. I.O.D connecter is to keep parasitic draw from running down the battery while new cars sit on the sales lot and should be plugged an at time of sale. Now it is more like a fuse that gets pushed the rest of the way in at sale day.
Great you found the leak! And you know your carb is in good shape with brass floats.
Yep now your on to the 19.5 wheel search.
Bill |
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Elite Veteran
Location: Medford, OR | Yep, I have some new shiny parts....Maybe a coach will come up for sale cheap locally with a set of 19.5's....Another coach that's been sitting under a tree somewhere.....who knows. Problem is, IF I do find this cheap local coach, Katie will have a club in her hand ready to beat me over the head if I even TRY to bring it home....lol |
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Contributor
| Andy: I am new here but have had lots of vapor lock experience with a 440 in a Vogue. Did you ever solve the problem?
Bruce ON EDit: I se you solved the problem. Congrats!!!
Edited by Bruce 2017-02-09 6:50 PM
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To vapor lock, or not to, that is the question.