Wont start when hot.

[1980corvettegibson]

My 1980 Corvette wont start when its hot. It used to start very well when it gets hot, acually better than when its cold, but now it wont start at all. It sounds like its not getting any fuel. Could it be the automatic choke? and if so, how do i replace it? I have a book that says it could be the starter worn, but would it still start when its cold if it was the starter? Thank You

 

[Yoda]

Does the starter engage (turn the engine over) and try to start, when everything is hot??

You can pretty much eliminate the starter if it turns the engine over and the engine just doesn't fire... if this is the case, does the engine flood out??

Then you need to know if you are getting spark from dist to the plugs.. if all is ok then I'd check timing and dwell before tearing into the carb and choke

Bud

 

[I_R_DA_ONE]

It sounds to me like you are getting vapor lock....all the gas is boiling out of the carb...
the thing to do is put a spacer between the carb and the intake....what have you done lately to change the starting of the motor????? and don't forget to check the EGR valve it may be stuck open.... if there is no spark when under these conditions check the coil in the distributer or the pickup sensor...electronic failure...
Mike R

 

[1980corvettegibson]

Thanks...it does start when its hot...it just is very very hard and barely starts. I havent done anything to the car to make it not start right. I have had battery problems though and wonder if that might be causing it. When its cold, it always starts on like the 3rd time..its always done that, then it would get hot and start everytime very great. and just lately i drove it bout 30 miles and got out and got in and it started right up..then when i got out agin and tried to start it, it just wouldnt start. It cranked but it was like it was getting no gas. So i held the gas pedal to the floor and it barely started. It sure could be flooding out, cause it smeels very strong of gas most all the time i drive it but how can i stop it from flooding out? my dad said something bout a floater being stuck, but i dont know what that is. The air filter is brand new. One time i tried to start it and it was hot, it made a loud grinding noise and smelt real weird. I have put a new radiator on it , new thermestat, and new battery. I will check the spark plugs, cause they havent been changed in awhile, then i might try fuel filter. Thanks for the help

 

[srs244]

if you smell gas all the time you could have the carb set to too rich a mixture setting, or as your dad mentioned, the carb float could be hung up. the carb has a reservoir in it with a float that keeps it full to a certain level so that there is always fuel available when you step on the gas pedel. while you are under power, gas is constantly flowing, so the effects of a hung float are less obvious. it "floats" and at a given lower level, opens up the fuel lines to refill itself, kind of like the same action you get inside the tank of a toilet. fluid is maintained at a level sufficient to function and once discharged to a certain lower level, the float activates a valve to refill the tank. the easiest things to check would be (in this order in my opinion): the choke operation (hanging up closed), the mixture settings on the carb, then the float function (you have to partially disassemble the carb (take the top plate off) to examine the float and its functioning. it is also possible that your fuel line in the engine compartment is too close to a hot surface and the fuel is percolating in the line (creates loads of air in the mixture and the engine won't run on air no matter how much we would like it to). this would be most obvious when left sitting hot because the start up would seem like the engine wasn't getting fuel (it would have too much air in it). the excess fuel smell at that point would be from your attempting the old "flooded engine restart" (foot on the floor, engine cranking until it starts). this of course would not be the case if the fuel smell is always there, not just on the restart. while i don't think it could be the fuel filter (based upon your description), i would still replace that (cheap insurance to say the least). i don't know if the 80 has a small filter at the end of the fuel line where it enters the card or not, but if it does, i would dump that as quickly as i could (unless you have an NCRS car) and replace it with an in line see through type filter. i put one both in front of and behind my fuel pump. i know it is probably overkill, but at $3.00 each it guarantees that the fuel from my 28 year old tank bladder is as clean as possible on it's way to both the pump and the carb.


i hope some of this is helpful to you.

steve