VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1917 Buick vapor lock

Fuel line insulated.. engine heat normal.. still happens..any help ???

Not familiar with 1917 Buicks. Do they use gravity feed? Air pump to pressure fuel tank? Vacuum tank fuel pump? Or ??

The first two are not prone to vapor lock as they don't have to draw the gas from the fuel tank. Vacuum tanks can vapor lock but it is rare unless there is a restriction in the line from the fuel tank.

Has vac. pump and electric back up...dosen't help problem???

Just wondering,does the '17 Buick have the same carburetor heat control system as the later model Buick's?If it does,it might be worth checking that all the levers and control rods are free,as if they lock in the "Heat On" position,you could experience vapour locking.
Another thing to check,would be the tubes that carry the exhaust gasses in the heat control system,to make sure that they don't have any pin holes in them,as this would cause a weakening of the fuel mixture due to the petrol/air mixture being diluted by exhaust gasses.

My dad has a 16 Buick will ask him, How is your fuel tank, I spent weeks with my 28 chevy trying to figure out why there was a fuel restriction, turned out here was a flake of rust wedged in the fuel line like a butterfly valve every once in a while it would rotate and block the line i'd take off the line blow down it and all was fine had to poke a wire down the line and pop it out, RAY

You need to locate where is the problem? Is it the flow of fuel to the carburetor or in the carburetor? Or somewhere else?

When you check the vacuum tank does it have fuel in it when the problem occurs. If not most likely a restriction in the fuel line from the tank or crud in the tank blocking fuel pickup tube. Or could be a vacuum leak reducing pumping of the fuel from the tank. Or one of the valves in the vacuum tank not sealing properly.

Is the carburetor fuel bowl empty or very low on fuel when it is checked? If so then too much heat in carburetor that is boiling the fuel. Too low a float level or if there is fuel in the bowl then too much hot air to the carburetor causing an incorrect mixture.

When the problem occurs can you squirt carburetor cleaner into the inlet of the carburetor and get the engine to run? If that is the case it might be a blockage in the carburetor.

If both carburetor and vacuum tank have sufficient fuel and will not run better with squirt of fuel or carburetor cleaner into the carb inlet, look at the ignition system.

Thanks for the info. I'll start by bypassing the vac. tank

It would be a good idea to check the exhaust heat supply to the carb (mentioned above). On my '15, there is a butterfly valve in the Marvel carb that works with the throttle. When I first got the car going, I had it the wrong way around, closed at idle and open at revs. It vapor-locked like crazy. I thought about it for a while and realized I had it working opposite to how it should. I reversed it and it has been fine for 30 years.

Regards
Al

( if all else fails, a little diesel added to the gas will work, say a quart per 6 gallons)