Q-jet Carb Trouble

[Blue85]

So heres the problem, when the truck sits for a couple days, it is a complete pain in the a** to start, cranks and cranks for a long time, and then slowly starts to fire, once its running once during the day it will start perfectly barley even turn over and she's running. Any ideas on whats happening, ever since the carb was rebuilt it has been doing this, and to top it off the guy that did the rebuild has skipped town.

[regal8r]

IIRC thats just how a carburated engine is...do u pump the pedal before starting it after it has been sitting a while? if so, your accelerator pump might be shot. could also be a fuel pump problem.

[LockDoc]

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Don't know if this is your problem or not but it sounds like it.

http://ramchargercentral.com/index.p...howtoshow;id=6

LockDoc

[Blue85]

regal8r, my other trucks fire right up, even after sitting for a month, and yes i giver a pump or 2 to prime it and set the choke.

[pimperout]

i have the exact same problem i have found that when i pump the gas exactly 5 times it will fire up like nothing

[regal8r]

Originally Posted by Blue85

regal8r, my other trucks fire right up, even after sitting for a month, and yes i giver a pump or 2 to prime it and set the choke.

sounds like its a fuel pump problem then

[Blue85]

thought about the pump, but if i pull the fuel filter from the carb, there is lots of gas in the housing, think i'm gonna swap carbs with another truck and see if it starts better if no difference then i'll try a different pump

[jhow66]

Sounds like your main well plugs are leaking. Carb is empty when you go to start it. Next time it sets for a few days before you go to start it pour a little gas in carb. If it starts right up and then dies this may be your problem.

[jhow66]

This will show you what I am talking about. (scroll down to #12 photo)
http://www.carcraft.com/howto/57178/

[oldiron]

I agree with jhow66 about the leaking plugs. Q-jets were famous for that.

[Blue85]

thanks for all of the input guys, i got another question for you, my buddy has a 81 that floods itself out when the motor is warm, and he shuts it off. Starts great when cold though, any ideas?

[cooters]

your buddy may have a choke that does not open completely. On yours, before starting , remove air cleaner and manually hit the throttle and watch for fuel to spray from the accelerator pump nozzle. My guess is there will be no fuel. Keep pumping till you see fuel, how many pumps does it take?

[sneakysnake]

I lightly scanned the above, Have you checked your "Acceleration pump" the one that squirts a stream of gas into the barrels when the pedal is pushed?
Sounds like you may not be getting the fuel you need for startup.

[WorkinLonghorn]

Jhow66 nailed it. That exact same problem (leaking Q-Jet) saved my last '69 from being stolen,they couldn't get it started. But I've heard that gas trickling down into your engine can wash away the oil in the cylinders and cause extra wear there so you really should pull it off and seal it up.

[Blue85]

Man do i ever love this site, tore down the carb today, and sure enough, I could see where the old expoxy was detereoraited and the plugs were leaking from, so i ground the old junk out and resealed with jb weld, find out tomorrow if it worked. Any other tips on things i could do with the carb while its apart?

[jacobs]

The nozzles where the fuel is discharged into the venturies from the accelerator pump will sometimes plug. I've had this problem several times. Right now, one of mine is plugged and I need to fix it. If both plug, it's the same symptoms as a bad accelerator pump.

[gmc1969custom]

It sounds like you have your problem solved but you might also want to make sure your choke is working properly, I was having the same problem a few weeks ago. My problem was my choke linkage, it was not allowing the front butterfly to close completely on a cool morning. Now after a little bit of tinkering and freeing up the linkage, I just get in my truck, pump it once and within 2-4 seconds she fires right up everytime. Pumping it a few times doesnt hurt anything, but IMO a properly tuned Q-Jet should only have to be pumped 1 time to set the choke and it should fire up within seconds.

[Blue85]

Well, i sealed up the holes, put a new accelerator pump in it, put it back together, installed it, and it fired up right away, now the real test is when i leave it overnight and see how it starts tomorrow. Thanks alot to everyone who helped me solve the problem.