37 Plymouth Problems

[Guest birdmannn101]

After driving my 37 Plymouth, the engine starts running real rough and will quit if I don't nurse it home with the manual choke. Believe it or not, the engine runs better for a few seconds with FULL choke applied. Does anyone have any help they can offer?

[keiser31]

Carburetor rebuild maybe. Dirt in the fuel line?

[ply33]

Could just be fuel starvation. Have he flex hose between the frame and the engine and the diaphragm in the fuel pump been replaced with materials that won't fail when running gas with modern additives?

[Guest birdmannn101]

Thanks for the info. The flex line from the tank to the pump was made by a professional tube maker out of flexible tube. I will look into rebuilding the carb since I did find some stuff in the bottom of the float bowl. Have either of you had problems with Bendix brakes tightening while driving to almost locking up?

[ply33]

Have either of you had problems with Bendix brakes tightening while driving to almost locking up?

If they are stock, the brakes should be Lockheed rather than Bendix.

Yes, the brakes can lock up if the relief port in the master cylinder is blocked either by dirt or because the rod between the brake pedal and the master cylinder has been adjusted too short.

[broker-len]

I have a 36 with almost the same motor,,,,,,,,,maybe you have a vacume leak,,,,,get the motor hot and put some oil in a pump oil can apply around head and manafold and carb gaskets it will suck the oil if there is a leak

[JACK M]

(fuel starvation). Check your fuel filter, pick and lines.

Not only for blockage but also air leaks. Sometimes air will leak in but gas wont leak out.

[Bill Wilkerson]

Without more info, I would offer the following possibilities:

Sediment in the system such as in the gas tank, fuel pump and / or carb. Sometimes, fuel can be drawn from a tank with fairly heavy sediment without causing noticeable problems UNTIL - during driving - fuel is added during the drive. This ''stirs up'' the sediment in the bottom of the tank which is then drawn into the pump & beyond.

You may also have a vacuum leak somewhere.

Other possible causes may be related to the ignition coil, condenser ( in the distributor ). the list goes on.

[Guest Ian.Harrold]

Is your heat riser stuck open?

[Guest birdmannn101]

I have a 36 with almost the same motor,,,,,,,,,maybe you have a vacume leak,,,,,get the motor hot and put some oil in a pump oil can apply around head and manafold and carb gaskets it will suck the oil if there is a leak

Broker-len, I went to the Plymouth club and while I was there someone mentioned that my car had a P-15 engine it since the number started with P-15. I have been in the past been running with the vacuum line off the metal vacuum tube that goes from left to the bottom of the carburetor. So I guess your right about running with a vacuum leak. Just recently I placed a tube with a screw in the end over that carb line because if I have the regular line attached all I hear is air rushing through the system. The wipers don't work but have been replaced with all new rubber.

[Guest birdmannn101]

Is your heat riser stuck open?

Are you talking about the valve on top of the engine that would be directed to the heater in the winter when you say "Heat Riser?"

[Guest birdmannn101]

Could just be fuel starvation. Have he flex hose between the frame and the engine and the diaphragm in the fuel pump been replaced with materials that won't fail when running gas with modern additives?

The only fuel additive I use is lead additive.

[ply33]

Are you talking about the valve on top of the engine that would be directed to the heater in the winter when you say "Heat Riser?"

Under the carburetor, where the intake and exhaust manifolds are bolted together there should be a rod protruding from the exhaust manifold with a thermostatic spring and counter weight. That directs exhaust into a "hot spot" in the intake manifold to assist in cold start drivability. If stuck in the cold position then exhaust gases will be heating the intake fuel air mixture more than you want.

[ply33]

The only fuel additive I use is lead additive.

Your engine came from the factory with hardened exhaust valve seat inserts. You have no need for leaded gas in that car.

There are modern fuel additives already in the gas you buy that can destroy older rubber compounds. For example your fuel pump diaphragm and the flexible hose between the frame and the engine. Unless you have rebuilt your fuel pump with modern materials (Antique Auto Parts Cellar carries kits) and replaced your flex hose you may have fuel starvation issues because of failed components in the fuel system. See: Plymouth First Decade: Are Gasoline Lead Additives Needed?