potential fuel starvation after start-up??

ridingrambling · October 03, 2019, 08:01 PM

Quote from: Rickf1985 on October 03, 2019, 12:37 PM
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By the way, A tip, wear mechanics gloves or nitrile or latex gloves when using that sealer because for some reason no matter how careful you are it WILL get on you and your tools. I don't care if the tools are across the room, it is magic, the sealer will find them! :)rotflmao Once on your skin there are only a couple ways to get it off. Carburetor cleaner, which is rough on the skin or it will wear off in a month or so. That stuff is one step above pine sap when it comes to sticking to skin!

Rick, is the Permatex type-3 you are referring to the stuff that is labeled aviation gasket maker?

Rickf1985 · October 03, 2019, 09:27 PM

Kind of a late answer but no, top and bottom are the same. You should see some imprint of how it was mounted on there. If you cannot see any imprint then you may not have had it bolted down tight enough and that may have been your problem. Using a 3/8 drive ratchet you should work in a cross pattern and bring it down to a fair tightness. Not really pulling hard on the wrench but a decent pull. There is a torque spec in the Chevrolet manual that I could look up or you could google it if you have a 3/8" drive or 1/4" drive torque wrench. Going to bed now. Will check in in the morning. Yes on the gasket sealer.

ridingrambling · October 03, 2019, 10:08 PM

Quote from: Rickf1985 on October 03, 2019, 09:27 PM
Kind of a late answer but no, top and bottom are the same. You should see some imprint of how it was mounted on there. If you cannot see any imprint then you may not have had it bolted down tight enough and that may have been your problem. Using a 3/8 drive ratchet you should work in a cross pattern and bring it down to a fair tightness. Not really pulling hard on the wrench but a decent pull. There is a torque spec in the Chevrolet manual that I could look up or you could google it if you have a 3/8" drive or 1/4" drive torque wrench. Going to bed now. Will check in in the morning. Yes on the gasket sealer.

Thx... yes, imprint very similar to old gasket... your description of how I mounted is basically what I did. Also, I could not find torque spec in GM chassis manual; but yes, I did find some specs via google. Not identical, but very close... gradually (via cross pattern) work from about 3ft-lbs each to somewhere between 12-15. Makes good sense. I did finally find my torque wrench this evening. One more benefit of this fiasco :-)... I pick up another new gasket tomorrow... hope to at least get it back to prior condition... then re-start the process... that is my hope anyway...
thx again for help... I (we) will get this.

ridingrambling · October 04, 2019, 10:53 AM

morning update:
picked up new mounting gasket... aim to re-install old carb to get engine running... while off I took a can of carb cleaner to it, and looked more closely at linkages, specifically choke (original suspicion of the high idle phenom that prompted me to decide entire new carb-choke install an good peace of mind idea :-( )

Well, the choke on old carb is very stiff, difficult to open, and just not right. Almost certainly the cause of the constant high idle before switching out carb.

Would like to address before re-installing (save yet another $10gasket, time, hassle). Really cannot work on choke while carb on engine. Just no room to manipulate.

My concern is, installing new choke on carb, getting linkage correct, etc., kind of looks more challenging than dropping in entire new carb (part of my original decision to replace dirty old carb setup). Plus, not sure I can find choke locally, so yet another mail order delay...)

Had I gone this route 10 days ago I'd likely be half way to California by now... oh well.

Rickf1985 · October 04, 2019, 01:04 PM

It is an electric choke right? Is it held on by screws or rivets? You should be able to get a replacement choke housing at any local parts store. There is very little to get "stiff" in the choke linkage. Can you tell if it is the linkage or in the choke pot? I always drill the rivets and replace them with screws after tapping the holes but you might not have the stuff needed for that. Once that is done the choke is adjustable. I don't like the engine screaming for long periods. I want the choke closed to get it started and run at high idle for a minute or two and then I kick it down and just let it idle for 10-15 minutes at idle to warm up. It is an RV, who is in a hurry?

ridingrambling · October 04, 2019, 01:44 PM

Yes, the choke on old carb is held by rivets. New one is adjustable. I looked for parts locally and nobody seem to have the housing/thermostat, unless I did not ask for right part. But you are right inline with what I was hoping I could do... however :-).
When I got old carb back on, it did start up, without the lean symptoms, but it coughed and gagged and then stalled after a little bit, sounded like flooded... would not restart (flooded symptoms).

Took old carb back off and there was a pool of fuel puddled in the intake... I must have cranked it too long trying to get it to kick over... my bad.
Was disappointed it would not return to the original condition at least (high idle)... Am letting it dry out at moment. Going to try carefully re-installing new carb and see if I get any different results from my first attempt, in case I did not get good air seal. Not sure I am optimistic, but at this point I do not seem to have a running engine with either carb, although symptoms slightly different with each.

Oh, I ordered choke pull-off. The old one seems to be crapped out... Still, even by hand the choke plate over the primary is extremely stiff, almost stuck, on old carb. Very loose on new carb.

Maybe I just did not do a good job with my first attempt at installing new unit. Nothing obvious is apparent, but I hope it was me and my next attempt is more successful and it is not the rebuilt carb itself...

A guy has to have hope :-).
Oh, and soon, I will have a new party trick... the ability to uninstall, re-install a quadrajet blindfolded... :-)... well, except for that damn mini cotterpin over on the accelerator linkage... what a pain in the butt!

ridingrambling · October 04, 2019, 04:10 PM

re-installed new carb second time... immediately started, stalled, backfire through intake with a flame that would make Gene Simmons proud...
called the supplier, shipping it back...

gotta figure out a plan B, with time of the essence...

Good thing Death Valley isn't going anywhere I guess...

ridingrambling · October 04, 2019, 05:50 PM

Before re-installing old carb AGAIN, I studied the choke linkages, comparing the old to the new units. After about 10 minutes of poking around, I discovered the linkage on the old carb was not correct. A lever from pull off was in front, instead of behind choke lever. It was keeping idle plate nearly closed and "sticky." Figured out how to flip it.

Re-installed old carb... carefully... said an atheist prayer

... sprayed a little carb cleaner in to prime her, and...... she started up, coughed, and started idling!!!!!!!!!!!
I ran across the field with my arms raised like I just won Olympic Gold!!!!

now I better go double check everything... :-)

Rickf1985 · October 04, 2019, 07:29 PM

And there you go, you are now a bonafide, certifiable RV mechanic!

If it was keeping the choke plate partially closed I would say your gas mileage should get a lot better, At least up to 7 MPG!

TerryH · October 05, 2019, 12:23 AM

I've been following this throughout and have to say congratulations! Kudos for your persistence.
Ridingrambling, you are one who is not afraid to ask for help, accept it, try it and report back. Not to mention trying your own ideas as well.
Rick, as we all ? know is superior with almost any mechanical issue and many others as well.
Great reading and following of this topic.
Thank you both.
Did you take a video of your victory run?

tmsnyder · October 05, 2019, 07:13 AM

Couple of thoughts, I know that bend you are speaking of well. I recently tried to replicate that hard tubing from the qjet down to the pump on my GMC. I failed miserably and just put the old one back on even though it has a decent kink in the line from a previous owner attempting to change the carb filter. If I wanted to redo it, I think I'd use a 90 degree flare elbow and a short piece of steel tubing to get in there close behind the carb instead of bending the tubing.

In order to disconnect that fuel line, for instance if I need to change the inlet filter, I found that it is necessary to take the four manifold bolts out and slide the carb backward an inch or so. First crack loose the fuel line with a wrench on the line and a wrench on the filter housing. Then crack the filter housing. Then pull the four bolts.

How is your in-carb fuel filter? If that plugs up you would have a fuel starvation problem. They are cheap, try changing it. Maybe you have contaminated fuel.

Also, don't rule out an Edelbrock 1411 with the necessary adapter plate #2696 iirc. Should be less than $500 total if you decide to give up on the qjet.

Good luck on your trip!

Rickf1985 · October 05, 2019, 08:49 AM

I have no problems getting my fuel lines off once the fitting is loose. I think his problem was that he could not get the fitting loose. The line only needs to move back 1/2" to clear the fitting. If you do not have line wrenches this can be an issue.

ridingrambling · October 06, 2019, 07:32 AM

Quote from: Rickf1985 on October 04, 2019, 07:29 PM
And there you go, you are now a bonafide, certifiable RV mechanic! If it was keeping the choke plate partially closed I would say your gas mileage should get a lot better, At least up to 7 MPG!

7mpg would be a nice win :-)

ridingrambling · October 06, 2019, 07:36 AM

Quote from: Rickf1985 on October 05, 2019, 08:49 AM
I have no problems getting my fuel lines off once the fitting is loose. I think his problem was that he could not get the fitting loose. The line only needs to move back 1/2" to clear the fitting. If you do not have line wrenches this can be an issue.

Yes; could not get the old fitting loose while carb installed. I eventually did get it off with the carb on bench... but it was very difficult. replaced with new flare fitting.

ridingrambling · October 06, 2019, 07:46 AM

Quote from: tmsnyder on October 05, 2019, 07:13 AM
Couple of thoughts, I know that bend you are speaking of well. ... If I wanted to redo it, I think I'd use a 90 degree flare elbow and a short piece of steel tubing to get in there close behind the carb instead of bending the tubing.

How is your in-carb fuel filter? If that plugs up you would have a fuel starvation problem. They are cheap, try changing it. Maybe you have contaminated fuel.

Also, don't rule out an Edelbrock 1411 with the necessary adapter plate #2696 iirc. Should be less than $500 total if you decide to give up on the qjet.

Good luck on your trip!

My thinking was similar to yours, but I tried every automotive place within 30 miles and could not find a flare elbow or anything close :-(... I ended up using some flexible stainless covered hose ("Spectra" I think). Was a bear to get onto the steel line on fuel pump side because of everything in the way, but I seem to have it secure. Recreated the "S" turn and it is working without any kinks.

I did check filter on new carb. It was installed correctly.

I have considered converting to a different carb; but time and $$ both factors at moment. I know mine is still not working ideal; but I think it will get me there. When warm, I often get some dieseling, especially if I don't run 93octane. With local price difference between 87 and 93 about 70cents/gal, I just could not get myself to fill a 3/4 empty tank with 93. I have a 3000+ mile trek ahead. Plan is to run 93 when I get to mountains. If I need to I will get by with shutting down in gear. I'd MUCH rather get all the quirks worked out; but I also really need to get on the road. Unfortunately, my old carb does not have adjustable idle mixture screws OR adjustable choke. Those were two reasons I had decided to put new carb on. So my carb projects not done; but not now...

ridingrambling · October 06, 2019, 07:53 AM

Quote from: TerryH on October 05, 2019, 12:23 AM
I've been following this throughout and have to say congratulations! Kudos for your persistence.
Ridingrambling, you are one who is not afraid to ask for help, accept it, try it and report back. Not to mention trying your own ideas as well.
Rick, as we all ? know is superior with almost any mechanical issue and many others as well.
Great reading and following of this topic.
Thank you both.
Did you take a video of your victory run?

Thank you.
This is a cool community. I had been lurking for a while; but had never posted prior to my frustration with this issue. I am super appreciative that Rick and others chimed in so quickly and helpfully. It helped me think through things, and also confirmed I was not crazy.

I will admit, for well over 1/2 century, I have felt completely clueless/inept regarding anything to do with engines. I have gradually been getting my hands dirty over past couple years on as needed basis. I still know very little; but each project gives me a little more insight, lessens the mystery, and gives me a smidgen more confidence I will get it figured out. It often takes a LONG TIME; but it still is satisfying. "Nice" thing about living in 30-year old Winnie is that there is never a shortage of projects to learn on :-)...

Rickf1985 · October 06, 2019, 10:06 AM

You should be able to run regular gas in that with no issues. If it is dieseling, (which is running on after shutting it off) then it is idling way to fast which is very hard on the transmission going into gear. If your definition of dieseling is actually pinging going down the road then the timing is off, advanced too far. Should be around 6 degrees with the vacuum advance line off and plugged and the idle set at around 650 RPM. You do NOT want to keep running it with it pinging since you are risking at least a blown head gasket or worse, burnt valves and holed pistons. There will be a diagram on the air cleaner that shows where all of the vacuum lines should be running. You might want to make sure they are all in the right spots.

ridingrambling · October 06, 2019, 11:11 PM

It is dieseling sometimes... idle still a little too high, but not as bad as before choke linkage fix, and not every time. I still think choke needs repair. I will double check the vacuum lines. thank you.

tmsnyder · October 17, 2019, 08:10 AM

Did you change spark plugs in this? Get OEM style plugs in it if not. If you did, make sure they are not plugs designed to run at higher temperature. They used to have plugs that would run hotter to keep them from fouling, maybe that's what's causing your dieseling.