1950 Roadmaster 8 will not turn over when HOT


This one has me stumped. The engine turns over and starts when the it is cold or warm. When the engine is HOT, I press the accelerator pedal to start, there is no electrical connection at all. There is no turnover. The starting system is dead.
With the key in the on position, everything works, radio, lights, horn when cold or hot.
I have had the carburetor rebuilt, starter rebuilt, bought rebuilt distributor and replaced points, condenser, coil, plugs and plug wires. Its seems all my troubles started with the carburetor rebuild, so I am thinking the issue may be the accelerator vacuum switch and not sure how to check it.

When the engine starts, I runs great with no problems. Turn it off after driving 7-10 miles the starting system is dead as road kill.


Active Member
There are two screws opposite each other on your vacuum switch. When it fails to start jump from one screw to the other with a jumper wire. If it turns over your problem is the switch.


Active Member
Leo, suntree is spot on. Depending on which carb you have, the "vacuum" switch is just a ball or piston that drops down and connects the two wires together . Vacuum when the engine is running, sucks the ball up, breaking the connection. It is probably sticking in the up/open position. Next time the no start happens, use a jumper [ I have used a pair of pliers in my younger days] to connect the wires. OR disconnect one wire and touch it to the other. Please let us know how this turns out. Here and on the other sites .