How come my 71 will not start after it warms up?

[mrhiggins312]

New to me 1971 convertible super starts great in the garage; but once I've driven it for more than 30 minutes it has trouble (lots) with turning over again. Battery is charged and try to start but wont turn over. Recently tuned and gone over by a 'professional' air called mechanic but problem persists.

[Matt Wilson]

Sounds like it may be heat soak. When the engine is cold there is a tiny gap between the valve and the rocker arm adjuster screw. After it's warm, the metal expands closing this gap. If those gaps are not adjusted properly, the valves could be held open and you essentially don't have much compression for the engine to run. Then you'll kill your battery, starter or ignition switch trying to figure get it started again. I'd say it's worth checking your rocker arms on a cool morning after the car sat all night. Worth learning how to do if you are new to these cars.

After these engines warm up and then are shut off, they soak up the heat from the exhaust and the fuel in the carb gets hot, making it tough to start. If the carb and engine is tuned properly, you might try keeping your foot to the floor on a hot start rather than trying to pump the accelerator, which risks flooding the engine.

If it's vapor locked, a friend can hold their hand over the carb air intake and you work the key. This'll help suck fuel back into the carb to get it running again.
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1972 Standard Beetle
1969 Baja Beetle

[mrhiggins312]

Wow... thanks. That was an issue I had a couple decades ago on a 67 I owned but this happens a lot quicker and I had not considered it yet. Yes when I get out and let the wife start it the card trick works like a champ. Guess o have a small job to do once this heat lets up!! Thanks again.

[Deebs]

Just in case it is vapor lock, check this video out. Might be an easy fix if you have some sand paper!

https://www.youtube.com/watch?v=eU6aVBW71Es

[mrhiggins312]

So I was able to drive and the trick worked to keep the pedal down. Played with Carb air intake and downed if I dent replicate so this weekend I will first try the sanding trick... then i will move the fuel line to see if either of those fix it. Thanks!!

[Joey]

Have you read the owner's manual on how to properly start a warm engine...

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Joey

‘60 Kombi - '74 Bus - '79 Panel - '65 Beetle