Re: Don’s 1937 (120) 138CD Deluxe Touring Limo

Posted by TxGoat On 2024/3/23 10:56:32

The tailpipe soot and a few drops of water are normal when an engine is idling in cool weather, especially if the car has been started, but not driven yet. Starting the car and backing out of a garage can be expected to cause this condition in anything but hot weather. There is always some soot in the exhaust system, and normal water condensation in the cool mufflers and tailpipe tends to wash some of it out.

The gas leaking at the throttle shaft could indicate "percolation" from engine heat, or it could indicate a high float level, a leaking float valve, or possibly a leaking check ball or gasket in the carburetor. If the leak shows up when the engine is started cold, and run for a minute or two, then shut down, it is not caused by percolation. The most likely cause would be a leaking float valve.
Normally, when an engine is shut down, there is some fuel pressure left in the line from the pump to the carburetor. This can be enough to cause flooding if the float valve leaks, even though the pump is not operating.