Ruff 2nd start after warm

Sounds like vapor lock. Here's an intriguing if not untrue story of one man's troubles with a car allegoric to vanilla ice cream:

General Motors:

This is the second time I have written you, and I don’t blame you for not answering me, because I kind of sounded crazy, but it is a fact that we have a tradition in our family of ice cream for dessert after dinner each
night. But the kind of ice cream varies so, every night, after we’ve eaten, the whole family votes on which kind of ice cream we should have and I drive down to the store to get it.

It’s also a fact that I recently purchased a new Pontiac and since then my trips to the store have created a problem. You see, every time I buy

vanilla ice cream, when I start back from the store my car won’t start. If I get any other kind of ice cream, the car starts just fine.

I want you to know I’m serious about this question, no matter how silly it sounds: ‘What is there about a Pontiac that makes it not start when I get vanilla ice cream, and easy to start whenever I get any other kind?'”

The Pontiac President was understandably skeptical about the letter, but sent an engineer to check it out anyway. The latter was surprised to be greeted by a successful, obviously well educated man in a fine neighborhood. He had arranged to meet the man just after dinner time, so the two hopped into the car and drove to the ice cream store. It was vanilla ice cream that night and, sure enough, after they came back to the car, it wouldn’t start.

The engineer returned for three more nights. The first night, the man got chocolate. The car started. The second night, he got strawberry. The car started. The third night he ordered vanilla. The car failed to start.

Now the engineer, being a logical man, refused to believe that this man’s car was allergic to vanilla ice cream. He arranged, therefore, to continue his visits for as long as it took to solve the problem. And toward this end he began to take notes: he jotted down all sorts of data, time of day, type of gas used, time to drive back and forth, etc. In a short time, he had a clue: The man took less time to buy vanilla than any other flavor. Why? The answer was in the layout of the store.

Vanilla, being the most popular flavor, was in a separate case at the front of the store for quick pickup. All the other flavors were kept in the back of the store at a different counter where it took considerably longer to find the flavor and get checked out. Now the question for the engineer was why the car wouldn’t start when it took less time.

Once time became the problem — not the vanilla ice cream — the engineer quickly came up with the answer: vapor lock. It was happening every night, but the extra time taken to get the other flavors allowed the engine to cool down sufficiently to start. When the man got vanilla, the engine was still too hot for the vapor lock to dissipate.

Robert's story, lighthearted as it may be, certainly could point to the cause.  Look for a spot where the fuel line passes close to a heat source.  If yu find such a spot, move the line away from it and see if that helps with the issue.  Since all of these cars are different from one another, there's no telling how things are laid out.  Good luck.

I agree that it sounds like classic vapor lock and Lane’s recommended fix should work.  You’ve recently changed the fuel hoses and somewhere a fuel hose is probably lying on the engine tin right above an exhaust pipe.  Move the hose away from the heat and the vapor lock should disappear.

Something to consider for the future, and permanently eliminate vapor lock, is to replace the mechanical fuel pump on the engine with an electric (preferably rotary) fuel pump up front underneath the gas tank.

Why go to all that bother?   Well, the mechanical fuel pump is a “sucker” that pulls the fuel from tank to engine.  The pulling action is more susceptible to fuel loss due to vapor lock because it’s harder to pull all of the boiled gases through the hoses to the engine.

OTOH, the electric rotary pump is a “pusher” that pushes new gas from the tank to the engine and pushes the vapor lock gases right along with the fresh fuel, overcoming the block.

I find that when my car is warm, the quickest way to start is to simply hold the gas pedal VERY slightly off the idle stop. DO NOT PUMP it. Just hit the key and slightly open the throttle plate.

If that doesn't do the trick, a full tune-up may be in order, starting with an ice-cold valve adjustment.

It certainly is NOT like an American V8 in any respect except that it has pistons, pushrods, rocker arms, and overhead valves.

Always set timing with a timing light, "by ear" may not be the ticket here.

This problem could be a) your starting technique, b) engine state of tune, c) too much fuel pressure, d) leaking float valve in carb, or e) actual vapor lock.

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My car has always done exactly the same thing, but I've learned how to deal with it.

In my case, I hold the pedal down a bit while cranking - something I never have to do if the engine's cold. But every car with this issue is different, so you will need to find what works best for you.

I do find that opening the engine lid to allow heat to escape when parking a hot engine usually minimizes the problem and sometimes eliminates it altogether. You might try that as a first resort to see if that makes a difference.

I've spent quite a bit of time on carb tuning and setting timing. It generally runs like a top from cold start right up through fully warmed up. But it's always been a little reluctant to start when parked hot and restarted after about 5-10 minutes.

If nothing else works, you might have to give up vanilla ice cream.

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"If nothing else works, you might have to give up vanilla ice cream."

I dunno, Mitch.  Somethings are worth sacrificing for.

@Sacto Mitch posted:

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My car has always done exactly the same thing, but I've learned how to deal with it.

In my case, I hold the pedal down a bit while cranking - something I never have to do if the engine's cold. But every car with this issue is different, so you will need to find what works best for you.

I do find that opening the engine lid to allow heat to escape when parking a hot engine usually minimizes the problem and sometimes eliminates it altogether. You might try that as a first resort to see if that makes a difference.

I've spent quite a bit of time on carb tuning and setting timing. It generally runs like a top from cold start right up through fully warmed up. But it's always been a little reluctant to start when parked hot and restarted after about 5-10 minutes.

If nothing else works, you might have to give up vanilla ice cream.

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I hear ya.  I converted my old 52 truck to fi-tech Fuel Injection for a similar issue but I don’t want to go down that long path.. Going to just deal with it and drive the car. As always i just didn’t want to get stranded somewhere if something else was evolving..

cheers

@Sacto Mitch posted:

.If nothing else works, you might have to give up vanilla ice cream.

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@Lane Anderson posted:

I dunno, Mitch.  Somethings are worth sacrificing for.

Yeah, but vanilla ain't one of 'em...

All the posts above are on point. My experience with all air cooleds is that they are a little harder to start once they're hot. And they're very quirky; if stopping for gas and it's a short time it starts right away. If, for example you go into the store to get a couple of things and it takes you a little longer then it becomes more difficult to start. If you have a long stay at the place; such as going in to eat, etc. then the car will cool off completely and start easier again.

I used @DannyP's method for the first time last Saturday on my Spyder. Perfect. Prior to that, to restart after a few minutes, I'd not touch the pedal until the engine "caught"-usually two revolutions. But if it didn't start then I'd have to go to the floor and crank. Danny P's way seems much better and more consistent from 5 minutes after shutdown to over an hour.

Thanks, man!

No problem, Ed. I don't know anywhere near a lot, but after 40k I've learned a little bit here and there.