So my 78' Powerwagon has been acting funny recently. Its gotten pretty warm here in south MS and when I turn the truck off for a few minutes say from 10 on its really hard to start back up. If i start it in under 10 it usually fires up really quick. Does this sound like vapor lock. I put a new carb,coil,plugs, filters, and fuel pump on it over the winter. The truck runs fine once it fires it's just hard to start, any suggestions? I haven't checked the timing yet but I think thats fine.

what carb did you put in it? the new gas has more alcohol in it, and boils off faster. the new carbs arent made with the same metal as older ones, and they conduct heat, instead of reflecting it. i had this issue after adding an edelbrock carb to my lrx. a phenolic spacer and looking for real gas, with no alcohol, was the solution.

I may have gone a little overboard on my attempt to keep the vapor lock from returning. But here is a list of all the items that I have changed:
- 1o battery cables
- 1025 cca battery
- moved the ignition coil from the motor to above the brake master cylinder
- 1/4" fuel return line
- fuel pump heat shield
- starter wrap
- (2) Cometic 3/8" thick carb isolation gaskets + carb heat shield/deflector
- lowered the fuel level in the bowls to allow some expansion during cool down
- removed the excess intake gasket at the heads to allow the "U" shaped area in the heads to dissipate the heat.
- run cool heat range spark plugs
- opened up the hood vents to allow heat to escape
- mini starter

Its a Holley on an edelbrock intake. I thought about trying a phenolic spacer and seeing if it'll help.

i see two real problems. the lowering of the fuel level only adds to your dilemma. the less fuel in the bowl, the faster it's going to boil/evaporate off. you need the fuel level at the middle of the sight glass, or bleed off hole, (or whatever the carb manufacturer calls for) and secondly, it sounds like you've uncovered the heat crossover, allowing even more heat to soak into the manifold, and carb. the electrical stuff you're doing has no impact on vapor lock, or fuel boil. reducing the temp into the manifold and carb, and keeping a proper fuel level is the key. raise the fuel level, block off the heat riser/crossovers, and look for good gas. just my

""it sounds like you've uncovered the heat crossover""

I do not believe that the "U" shape on the outside of the heads is the heat crossover that you are referring too. From what I understand, this "U" shape allows the heat to escape away from the heads. I was allowing the intake gasket to cover this area until a board member showed me that I should be cutting the gasket back to allow the heat out.
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"" the electrical stuff you're doing has no impact on vapor lock, or fuel boil""

The electrical stuff that I have done keeps the heat out of the electrical items under the hood. This does help on hot restarts. (The original poster has not proven if this is fuel or electrical items heating up.) I was giving the OP my opinion on other items that he could look for.
I was not aware that your opinion is the only one that counts!!
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""the lowering of the fuel level only adds to your dilemma. the less fuel in the bowl, the faster it's going to boil/evaporate off"".

You have a good point but my QF bowls are huge. If I run my bowls at the half way level then as the car shuts off and sets, the fuel rises to the top of the bowls and you can smell the gas fumes coming out of the carb. If I run my bowls at the bottom of the sight glasses, then the fuel only rises to the half way point and the gas fumes are much more tolerable in the garage during cool down.

I was only trying to help the original poster and I was not intending to defend my own solutions to the problems that I have encountered.

A holley would have to be bone dry to have the fuel evaporation problem because the accelerator pump is on the bowl floor. I don't think it all could evaporate in as little as 10 minutes. After a good run park it, shut it down and remove the breather. Sit and watch the carb for 10 minutes. If you see what looks like smoke or steam coming out of the carb throat gas may be dripping into the intake and flooding the engine.

What Johnedod said, eyeball it after you shut it down

Hmmmm good suggestion I'll try that.