carb perculating?

[ray casonodessa]

i read about carb perculating, {fuel driping into manifold after motor is off , when hot} my carb does this all the time. cold motor, hot motor. whats up? help if you can. thanks in advance.

 

[rheltzel]

Couldn't truly be percolation if cold. If cold, bad float or float valve. Cure for true float bowl percolation caused by engine heat transferring to carburetor, is a phenolic spacer between manifold and carburetor to block/reduce latent heat transfer.

 

[flatjack9]

What kind of carb?

 

[Binx]

Cold motor: Make sure you're using a vented gas cap.

Hot motor: Try using non-ethanol fuel sold at the marinas or wherever you can find it.

Lonnie

 

[ray casonodessa]

its a 94. i changed the needle and seat and took the gas cap off. from what i see is the fuel drips out of the nozzle bar onto the butterfly and drains into the manifold. making for hard restarts .

 

[flatheadmurre]

Bad powervalve probably.

 

[flatjack9]

I don't think a bad power valve will show leakage from the nozzles unless the engine is running.

 

[scicala]

Bad powervalve probably.

NO !

Sal

 

[scicala]

Float is set too high, or sinking are the most likely causes.

Sal

 

[tubman]

I wouldn't be so quick to eliminate the power valve as the problem. I've run all many 94 carburetors, and most of the time, if they leaked, it was the power valve. Just sayin'.

 

[flatheadmurre]

If it dumps the fuel down into manifold standing still giving starting issues, my first guess still is powervalve or bad gaskets.
Float would give a bad running engine and from what i read its more a problem of dumping fuel then running rough.

 

[flatjack9]

I don't think it is possible for the fuel to go uphill from the power valve chamber to the nozzle bars without some sort of suction. That would be like saying the jets were causing the problem.

 

[ray casonodessa]

I just took it apart again and found there was gas inside the float. replaced the float and it was 9 out of ten better. little drip every once in a while. removed top and put the old needle and seat , adj. float again . so far so good , no drips . I will keep an eye on it for a while. by the way I did have them rebuilt at a vintage carb shop.

 

[supereal]

A common cause of carb leaks is a warped body or lid casting, usually from overtightening the screws. When we rebuild a carb, we place a piece of fine grit paper on a piece of glass and rub the gasket surface across it. That will identify where it is warped, and if too severe, the surface can be restored by continued movement on the fine grit. Gas has a very small surface tension, and will easily leak making finding the source hard to find.