what causes vapor locks in gas engines, and how to avoid them from occurring?

Question

the heat is causing them to occur more frequently

Answer 1

The fuel in the line from the gas tank to the engine is heating past the boiling point and turning to vapor. All engines are designed to work on gasoline in a fluid form...when it turns to vapor the engine will quit.

A couple of "old timer" tricks....

1. Wrap the fuel line that is accessible to you in aluminum foil. It helps deflect the heat.

2. Put several clothes line pins on the fuel line. (Don't ask me why this works, but it does.)

Answer 2

Vapor Lock most deffinelty has to do with altitude. Its one of the main causes due to the lack of air mixed with extra heat, the fuel starts becoming a vapor. This is a huge problem for people like this that come from the new mexico area and run our trails that are nearly 8000 feet higher than there garage where they tune. The car you might be talking about, is sometimes they installed a specific jet for that sales area, those can be purchased and used when rebuilding the carb. Deffinetly a Manual choke will help and making sure the electric fuel pump is working adiquitly. I run the electric pump through my manual stock pump and have not had any issues and i have been to 13600 and possibly higher with this jeep. Usually if your electric pump is working there should not be any issues. The times i have seen a vapor lock it has been in the pump, where the pump can not keep primed and sucks air or actually the vapor gas. I have seen people put snow or cold water on the pump and starts right up. Other wise its always a good time to relax and have a brew.

Answer 3

Vapor lock is caused by fuel boiling in the fuel line between the fuel pump and carburetor from hi underhood temperatures. It is rare or non existent to have a vapor lock condition with todays fuel injected engines because of the 40-55psi in the fuel lines. Whereas in a carbureted engine you may have only 5-10psi fuel pressure. If you have a carbureted engine,I would suggest disconnecting the mechanical fuel pump and install an aftermarket in-line electric fuel pump as close to the fuel tank as possible,you will also have to run a section of 14 gauge wire from a source that feeds 12 volts to the pump only when the ignition switch is in the on position,play it safe and install an inline fuse to the new pump as well. Where your existing fuel line is connected to the mechanical pump inlet,cut the end nut off and use rubber fuel line hose and new hose clamps in place of it and route it up to the carburetor fuel inlet away from any moving parts or hot surfaces. If all goes well for you with this procedure,you should never have to worry about a vapor lock problem again.

Answer 4

usually this is caused by a clogged vent pipe (on the fill neck for the tank) to check this put a small slit in the vent pipe with a razor knife see if the situation improves. also another thing to consider is blockage in the return fuel lines or a plugged fuel filter

Answer 5

todays fuel injected cars don't do that much but when you boil gas in the carburator it turns to a gas state like steam. in that form it will noy flow through the carb correctly and the fuel ratio now will not explode as it should...cool the gas and she'll start right up.