1969 F100 Fuel bowl leak down
 

I am posting this for ideas on WHY my carburetor bowl “leaks down” when the engine is HOT.
Specifics: 1969 F100 360 V8 Auto Trans (I am the original owner)
2100D 2 bbl carb manual choke (Original Carb)
Cold starting: excellent…never fails to immediately start
Hot starting: excellent if re-started within 3-4 minutes
Hot starting: poorer & poorer if re-started after 5 minutes

During the past year have installed TWO carb kits and THREE power values and the problem (leak down) continues. I can place the carb on the workbench, fill the bowl with gas and the full level remains for several days. So the problem seems to be “heat” but I simply cannot pin point the specific cause of the “leak down”. The fuel level will drop close to ½” within an hour but NEVER goes dry.

Thoughts?

Re: 1969 F100 Fuel bowl leak down
 

Place spacer betin carb and manifold not matal somthing that will not attackmanifold heat

Re: 1969 F100 Fuel bowl leak down
 

billwill has the right idea, the carb is getting hot and boiling fuel out of the carb, flooding engine and leaving carb empty, thus hard starting, put a spacer at least 3/4" thick between the carb and manifold, dont use an aluminum or hard plastic one, find a spacer that is made out of compressed fiber, they dont transfer as much heat, if your using an aluminum manifold that is one problem, cast iron work better, and this new gas with alcohol doesnt help , it boils at a lower temp

Re: 1969 F100 Fuel bowl leak down
 

Many of the 360's had a spacer from the factory that was a source of vacuum for the PCV. The spacers would corrode, causing an idle problem. Since you didn't mention that, you may have the only one that hasn't corroded yet. There were some phenolic spacers available that had the vacuum hose barb on the back. Look for one of those. I don't know if they were aftermarket or factory for one year. If you have a vacuum source on the carb, you can make a spacer out of hard wood.

Re: 1969 F100 Fuel bowl leak down
 

THANKS to the three members that replied to my carb leak down issue. I purchased a 1" phenolic spacer to replace the original heated carb spacer and it appears all my issues are in the rear view mirror. I had to work on the phenolic spacer with a router so the throttle would fully open and then added the large vacuum port for the PCV tube.

Well worth the time...appreciate the advice. NOW...now does anyone need a C7AE-9A589-A, original 44 year old heated carb spacer? From my recent experience I would put them in the recycle bin.