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Hi
I have a problem with my corvette 76. if I leave the car one day without starting, it takes a long time to start (about 10 seconds) I think the gasoline goes back to the tank
fuel pump. phenolic spacer. block heat passage in intake. all of the above. none of the above. cranking it until oil pressure starts to climb before firing is never that bad a thing.
At least in 79, the fuel filter has a check valve. Swapping this out helped a great deal with my car. Fixing the tuning also helped. Plus the above suggestions.
Still, 10 seconds isn't all that bad really. On a cold engine, pump the gas pedal twice to the floor to reset the linkages, then crank until it starts.
I've ordered a one-way valve for the fuel line, which I'm going to install between the pump and the carb.
When the car sits for a week or two, the fuel seems to have siphoned back out of the carb. I'm not sure how this is possible, but I know I have to crank the engine over for a while to get gas back into the float bowls. So, the one-way valve should do the trick by not letting the gas back out of the carb.
I think.....
Once the fuel is in the fuel bowls in the carb it is unlikely that it could siphon back to the tank, there is an air gap between the entry to the fuel bowl and the fuel level in the bowl. Do you give the accelerator a couple of pumps before trying to start the engine? Take the air cleaner lid off when the engine is cold and give the carb a couple of pumps while you look down the carb venturies to see if any fuel is squirting from the accelerator pump nozzles when you do this. If not the fuel could be boiling off when the car is parked up and the engine is hot. If there is fuel in the bowls it should be sufficient to keep the engine running until more was pumped up the line by the fuel pump.
At least in 79, the fuel filter has a check valve. Swapping this out helped a great deal with my car. Fixing the tuning also helped. Plus the above suggestions.
Still, 10 seconds isn't all that bad really. On a cold engine, pump the gas pedal twice to the floor to reset the linkages, then crank until it starts.
I've ordered a one-way valve for the fuel line, which I'm going to install between the pump and the carb.
When the car sits for a week or two, the fuel seems to have siphoned back out of the carb. I'm not sure how this is possible, but I know I have to crank the engine over for a while to get gas back into the float bowls. So, the one-way valve should do the trick by not letting the gas back out of the carb.
I think.....
I would be looking at the carb. I suspect it’s leaking. Ten seconds of cranking is required to refill the float bowls. Had the same problem with my ‘66. It was the carb.
2020 Corvette of the Year Finalist (performance mods)
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It could be just evaporating. I pump mine about 5 times, turn it over to see if it will catch, 5 more pumps to see if it will catch then just 3pumps and repeat. It varies on the weather as to how fast mine is evaporating and how many days since the last drive. once it sounds like theres gas in mine its just 1 or 2 pumps so I dont flood it. I have an Earls check valve in mine and I still have evaporation issues so I know its not syphoning out
One more reason for a Sniper fuel injection next year
Last edited by Rescue Rogers; Jul 3, 2020 at 09:39 AM.
It could be just evaporating. I pump mine about 5 times, turn it over to see if it will catch, 5 more pumps to see if it will catch then just 3pumps and repeat. It varies on the weather as to how fast mine is evaporating and how many days since the last drive. once it sounds like theres gas in mine its just 1 or 2 pumps so I dont flood it. I have an Earls check valve in mine and I still have evaporation issues so I know its not syphoning out
One more reason for a Sniper fuel injection next year
In my experience it takes a week or more for the fuel to evaporate. If it’s doing it in one day, it’s probably leaking.
All mechanical pumps have a check valve in, and a check valve out. Thats how they work.
The tank sock keeps trash out.of the pump.
Adding a check valve or foot valve is worthless.
