Hard starting when hot

[da_raabi]

Its about 92 out and the wife just got back from a 30 minute drive. Truck was really hard to start. Took quite a few turn to get her to catch, dropped off and tried again and kept it going with the pedal. Strong gas smell. Any reason why? Stock 454 with a quad carb.

 

[firebane]

Either the fuel is boiling out due to heat or the wells are leaking and causing the carb to go dry.

Either way.. rebuild time for the carb.

 

[MadOgre]

Hot soak

 

[350runner]

Well plugs leaking?

Sent from the dust in front of you!

 

[MadOgre]

If you have to hold the throttle to the floor to make it start, it is hot soak.

 

[da_raabi]

I didnt have to hold it to the floor, just keep it revved a tad. Any other time is starts just fine, although I do have to pump it a few times before cranking. When I do that though it fires instantly. Can you explain the idea of hot soak? How would a rebuild alleviate this?

 

[firebane]

I didnt have to hold it to the floor, just keep it revved a tad. Any other time is starts just fine, although I do have to pump it a few times before cranking. When I do that though it fires instantly. Can you explain the idea of hot soak? How would a rebuild alleviate this?

Quadrajets have a gasket that is usually 1/4" to 1/2" thick that goes between the intake manifold and the carb to help alleviate heat issues. Check to see if that is there first before anything else.

 

[garzas23]

What exactly is hot soak?

 

[firebane]

What exactly is hot soak?

The engine and intake is so hot that it simply boils off the fuel within the carb causing a no start or hard start issue.

 

[garzas23]

Ok thanks for the info.

 

[MadOgre]

Actually the heat causes the volume of the gasoline to expand and spill over into the intake manifold Thus you need to hold the throttle wide open to allow enough air as possible to mix with spilled gasoline to create an air/fuel mixture suitable to combustion