Thread: 390

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I have a built 390 that starts very easily when cold but after its run and sets a few minutes it takes a lot of cranking to get it started but always starts eventually, what could be causing this. It has electronic ignitioin and a Holley 750 carb.

The carb and the fuel in the carb are getting a heat soak after you shut the motor off, pushing fuel into the intake manifold, so you need a heat shield. There are different styles to fit different motors, so make sure you're getting one that will work with your FE Ford motor. Here's an example....
JEGS Performance Products 154055, JEGS Square Flange Carb Heat Shields | JEGS Performance Products

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Welcome to CHR! I agree with Tech, it sounds like you're boiling the fuel out of the bowls. I like that heat shield that he linked to, as it shields from radiant heat from the intake as well as the heat conducted through the base, but if you simply cannot abide that "look" covering so much area you might consider a thick spacer as a starting point, and see if that does it. They come in a bunch of materials, from wood fiber composites to phenolic, but you don't want the aluminum model. Summit has a ton of them, based on the bore of the carb - http://www.summitracing.com/search/p...9%2B4294949621

Originally Posted by rspears

Welcome to CHR! I agree with Tech, it sounds like you're boiling the fuel out of the bowls. I like that heat shield that he linked to, as it shields from radiant heat from the intake as well as the heat conducted through the base, but if you simply cannot abide that "look" covering so much area you might consider a thick spacer as a starting point, and see if that does it. They come in a bunch of materials, from wood fiber composites to phenolic, but you don't want the aluminum model. Summit has a ton of them, based on the bore of the carb - http://www.summitracing.com/search/p...9%2B4294949621

I have used a some of these and can tell you that a few minutes on a rouge wheel will polish the aluminum ones up very nicely.

I agree with Tech and rspears. sounds like a form of vapor lock. It can also be caused by fuel lines getting hot;

A vapor lock is more likely to develop when the vehicle is in traffic because the under-hood temperature tends to rise. A vapor lock can also develop when the engine is stopped while hot and the vehicle is parked for a short period. The fuel in the line near the engine does not move and can thus heat up sufficiently to form a vapor lock. The problem is more likely in hot weather or high altitude in either case.

After it sets, take off the air cleaner and see if the accelerator pump is squirting gas when you move the throttle. If not, it means no fuel in the bowls because of boiling in the carb like the experts have said. Don't follow the old maids advice of putting clothes pins on the fuel line. Why people used to think wood was a good conductor and would actually help is beyond me. On my 40, at 105-110 degrees climbing the Jerome mountain in Arizona, you could hear the fuel boil when we stopped. Took a heat shield and insulating spacer to cure it. The reason not to use an aluminum spacer is that it conducts heat just like your manifold. Heed the advice already posted, you will be able to fix it.