View original topic: vapor lock?
[email protected] Mon Jul 28, 2003 9:09 pm

hey my buddy has a 73 super beetle and he is haveing vapor lock problems. any suggestion would help? thanx smllthrck

j.pickens Tue Jul 29, 2003 5:24 pm

The generic aircooled vapor lock is usually caused by one or both of the following:
1. Incorrectly routed fuel line, usually where it comes around from in front of the fan shroud to the rear where the fuel pump is. If it's routed near the intake manifold, heads, or heat riser, (like lying in contact with one or all of them) the heat will cause the gas to boil in the line, especially when you stop the engine, and re-start it, or try to, while still hot.

2. Too many "up and down" bends in the fuel line, causing small gas bubbles in the line to break the column of liquid coming from the gas tank. The break causes the fuel pump to starve for liquid, no gas gets pumped, and the engine won't start.

Ususally its a little of both #1 and #2 together conspiring to F up your day.

In your '73 you may have some additional problems with various emissions control stuff screwing up the free flow of gas to your fuel pump. I'm not real familiar with these newfangled beetles, so somebody else may have some insight.

j.pickens Tue Jul 29, 2003 5:27 pm

I should add that the above assumes that your fuel lines are in good shape, and correctly attached to the fuel pump and carb. Cracked and leaking fuel lines can cause poor suction to the fuel pump as well.

vicsvw Tue Jul 29, 2003 6:23 pm

VW are not prone to vaper locks, we find the main cause is gas tank or fuel line cloged. Pull the fuel line off the carb and try to sphion several gallons into a can on the floor. The last gallon should run the same as the first. Make sure all vents are open (cap etc.)

j.pickens Tue Jul 29, 2003 8:39 pm

"VW are not prone to vapor locks"
LOL, maybe when new, and set up with all stock equipment they aren't, but I've seen MANY VW's with the "hot start vapor lock" problem, with the cause as described in my earlier posting.

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