The Ford Barn

Mulletwagon · 04-16-2019, 02:34 PM

Noticed an occasional drip from the bottom of the carb while engine running or off. The drip is not persistent, just a drop or two than it stops. Changed all gaskets and the float valve but the dripping has continued. Seems to be coming from the bowl bolt which holds the carb units together. After analyzing the bolt design it appears the bolt is not sealed from gas intrusion. Sloshing fuel in the bowl can reach the bolt, proceed down the bolt bore and exit through the slit in the lock washer. Is this normal ? Any reason I cannot replace the lock washer with a continuous plastic washer ?

Tom Endy · 04-16-2019, 02:46 PM

The drip is likely not coming from the bolt. What is probably happening is the float valve is not holding well and allows the fuel level in the reservoir to rise. As it rises so does the fuel level in the main and cap jets where they will overflow into the throat of the carburetor. The fuel will then run out the small drip hole in the base of the carburetor and run back and drip off the bolt.

Slide your little finger into the throat under the choke plate and if it gets wet with fuel it will confirm where the leak is coming from.

A Viton tip float valve will usually take care of this problem.

Tom Endy

chap52 · 04-16-2019, 04:32 PM

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Do you close the gas shut off valve when you shut down? If it is a float valve issue and the tank shut off is closed there has to be a supply of gas continuing to feed the carb.
Try closing the tank shut off valve then disconnect the fuel line from the carb over a catch pan, I use an old pie tin. Is there a visible amount of fuel still dripping after an hour or so? I just went through this and even after checking the float valve and level and rebuilding the tank valve I have a fuel drip. New valve on the way. Chap

04-16-2019, 02:34 PM	#1
Mulletwagon Senior Member Join Date: Jan 2019 Location: Florida Panhandle Posts: 585	Carb Drip Noticed an occasional drip from the bottom of the carb while engine running or off. The drip is not persistent, just a drop or two than it stops. Changed all gaskets and the float valve but the dripping has continued. Seems to be coming from the bowl bolt which holds the carb units together. After analyzing the bolt design it appears the bolt is not sealed from gas intrusion. Sloshing fuel in the bowl can reach the bolt, proceed down the bolt bore and exit through the slit in the lock washer. Is this normal ? Any reason I cannot replace the lock washer with a continuous plastic washer ?

04-16-2019, 02:46 PM	#2
Tom Endy Senior Member Join Date: May 2010 Location: Southern California Posts: 3,131	Re: Carb Drip The drip is likely not coming from the bolt. What is probably happening is the float valve is not holding well and allows the fuel level in the reservoir to rise. As it rises so does the fuel level in the main and cap jets where they will overflow into the throat of the carburetor. The fuel will then run out the small drip hole in the base of the carburetor and run back and drip off the bolt. Slide your little finger into the throat under the choke plate and if it gets wet with fuel it will confirm where the leak is coming from. A Viton tip float valve will usually take care of this problem. Tom Endy

04-16-2019, 04:32 PM	#3
chap52 Senior Member Join Date: Jun 2013 Location: Marana Arizona Posts: 1,776	Re: Carb Drip Sponsored Links (Register now to hide all advertisements) Do you close the gas shut off valve when you shut down? If it is a float valve issue and the tank shut off is closed there has to be a supply of gas continuing to feed the carb. Try closing the tank shut off valve then disconnect the fuel line from the carb over a catch pan, I use an old pie tin. Is there a visible amount of fuel still dripping after an hour or so? I just went through this and even after checking the float valve and level and rebuilding the tank valve I have a fuel drip. New valve on the way. Chap