trouble starting after a few days
05-11-2004, 09:37 AM
#1
Heel & Toe
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trouble starting after a few days
I am having trouble getting my 78 corvette started after it sits for a couple of days. It is not the battery as it turn over good. The carburator has been rebuilt also. I had to put some gas in the carb once after it sat for a week.
Could it be anything to do with the carb? I have also been told that it may be a problem with the fuel pump pulling gas back out of the carb. Any ideas?
Could it be anything to do with the carb? I have also been told that it may be a problem with the fuel pump pulling gas back out of the carb. Any ideas?
05-11-2004, 12:21 PM
#2
Melting Slicks
Re: trouble starting after a few days (SLVR25TH)
Is it possible that you're just having COLD starting problems? IE, how easy does it start after sitting all night? Might just be a choke problem. :cheers:
05-11-2004, 12:43 PM
#3
Le Mans Master
Re: trouble starting after a few days (marshrat99)
I have had this problem with Q-jets in the past. I've always heard that there is some sort of plug in the base that allows fuel to weep out over the course of several days. I have also been told that the fuel we use is much easier to evaporate than it was 20 or so years ago-this is also supposed to vary by season and region of the country. Maybe Lars will chime in.
05-11-2004, 12:57 PM
#4
Heel & Toe
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Re: trouble starting after a few days (SLVR25TH)
The last time I drove the car it sat for about 7 hours and was then hard to start. After it starts it runs fine and you can swith off and restart a few minutes later with no problem. May be a choke issue? :confused:
05-11-2004, 01:21 PM
#5
Le Mans Master
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Cruise-In VIII Veteran
Re: trouble starting after a few days (SLVR25TH)
The last time I drove the car it sat for about 7 hours and was then hard to start. After it starts it runs fine and you can swith off and restart a few minutes later with no problem. May be a choke issue? :confused:
05-11-2004, 01:27 PM
#6
Re: trouble starting after a few days (SLVR25TH)
The last time I drove the car it sat for about 7 hours and was then hard to start. After it starts it runs fine and you can swith off and restart a few minutes later with no problem. May be a choke issue? :confused:
Do this easy stuff first before you start ripping things apart ...
First, with the engine cold, verify that the choke snaps FULLY closed when you open the throttle. The black choke coil cover should be adjusted so that the alignment mark is on the second line to the "lean" side of the center mark. This should make the choke snap fully closed when the engine is cold.
Then, pull the short piece of vacuum hose off the pulloff (you should have a short piece of vacuum hose attaching the pulloff to the vacuum nipple on the carb). Attach a long piece of vacuum hose to the pulloff and suck on it. This should make the pulloff retract. The pulloff should hold a vacuum in this condition. If the pulloff does not retract, or if it will not hold a vacuum, you need to replace it.
With the pulloff fully retracted, apply very light finger pressure to the choke plate to simulate the light force of the air pushing on the plate. The lower edge of the plate should be open 1/4". You can measure it by slipping a 1/4 drill bit down bewteen the lower edge of the choke plate and the carb airhorn. Adjust the phillips head screw on the end of the choke pulloff lever to get this measurement right at 1/4".
With this set, hook up the short piece of hose again and start the engine. Fast idle speed is adjusted with the screw located unde the choke housing. Set fast idle to about 1200 rpm.
Then, pull the short piece of vacuum hose off the pulloff (you should have a short piece of vacuum hose attaching the pulloff to the vacuum nipple on the carb). Attach a long piece of vacuum hose to the pulloff and suck on it. This should make the pulloff retract. The pulloff should hold a vacuum in this condition. If the pulloff does not retract, or if it will not hold a vacuum, you need to replace it.
With the pulloff fully retracted, apply very light finger pressure to the choke plate to simulate the light force of the air pushing on the plate. The lower edge of the plate should be open 1/4". You can measure it by slipping a 1/4 drill bit down bewteen the lower edge of the choke plate and the carb airhorn. Adjust the phillips head screw on the end of the choke pulloff lever to get this measurement right at 1/4".
With this set, hook up the short piece of hose again and start the engine. Fast idle speed is adjusted with the screw located unde the choke housing. Set fast idle to about 1200 rpm.
05-11-2004, 03:03 PM
#8
Re: trouble starting after a few days (SLVR25TH)
Thanks for the advise. I will have someone check the choke.
05-11-2004, 04:28 PM
#9
Le Mans Master
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Re: trouble starting after a few days (wcsinx)
:withstupid: There are very few mechanics left that know how to reliably set a choke these days. Time to get your hands dirty! :yesnod: