Hard starting when hot - vapor lock?

[Eric 1151]

I used to have the same problem with my SPF. I wasn't starving for fuel, the heat under the hood was boiling the fuel in my carb when I shutoff and flooded the engine through the vents. If I held the throttle open and cranked, it would eventually start with a big cloud of black smoke. Now, at least 25 seconds before I shutoff the engine, I turn off my electric fuel pump and drain the carb by letting it idle. I also installed an Edelbrock carb insulating gasket. With my 557, I don't have enough hood clearance to use a wood spacer. No more problem. Worth a try.
Eric 1151

[SP01715]

Originally Posted by Eric 1151

I used to have the same problem with my SPF. I wasn't starving for fuel, the heat under the hood was boiling the fuel in my carb when I shutoff and flooded the engine through the vents. If I held the throttle open and cranked, it would eventually start with a big cloud of black smoke. Now, at least 25 seconds before I shutoff the engine, I turn off my electric fuel pump and drain the carb by letting it idle. I also installed an Edelbrock carb insulating gasket. With my 557, I don't have enough hood clearance to use a wood spacer. No more problem. Worth a try.
Eric 1151

This is your answer. My car does the same thing. I just put the pedal down to give it more air and it fires right up.

[PLDRIVE]

Had the same trouble. Made a heat shield and all my problems solved.

http://s540.photobucket.com/albums/g...DSC02558-1.jpg

[Ronbo]

Haven't heard it mentioned, but you could use freeze spray and cool different (suspect) items down to narrow down the culprit.

I also have one of those Snap-on air powered choke testers that's pretty handy for this type of stuff. Don't ask me how it works but you put shop air in and it blows hot air out one end and cold air out the other with no moving parts.

OK, did a little digging. Snap-on no longer sells it but here is one: http://www.exair.com/en-US/Primary%2...es%20Home.aspx

[cdog]

Originally Posted by Eric 1151

I used to have the same problem with my SPF. I wasn't starving for fuel, the heat under the hood was boiling the fuel in my carb when I shutoff and flooded the engine through the vents. If I held the throttle open and cranked, it would eventually start with a big cloud of black smoke.

I do this for my 521. If it sits less than 10 minutes or so, I make sure to hold the throttle open for about 30 seconds when I get in. It will fire up, but does shoot out some smoke. It only happens in the heat.

When I drove it in VERY hot temps, say 110+ in Vegas, it really didn't want to idle and had significantly more trouble starting. Idling in traffic it did not like. If I moved to Vegas, I guess I'd need to address this.

My 14" air cleaner doesn't leave much room for a carb spacer. Maybe 1/4"? I guess I could look at doing that. Or lowering the floats.

[Learjockey1]

I have Holley's, but check to make sure the little bendable rod that connects the primary shaft linkage to the secondaries is adjusted so it completely closes the secondary butterfly shaft when the carb primaries go to idle. If not adjusted correctly the secondaries are left a little open causing a lean starting condition with the engine hot. I do not believe you will not see this adjustment in any rebuild book or instructions. I never did, I noticed it when rebuilding the carbs. This fixed my problem a few months ago but never I came back on the thread to mention the fix.