The RPM's don't go down when I take my foot off the pedal on my 1940 Lasalle. I have to tap the pedal to get the RPM's to go down. I tried spraying WD-40 on the linkages on the outside of the carburetor. That helped a little. I already have two of the factory original return springs on the linkage. What causes this?
Could be that the bushings/bearings on which the butterfly valve rotates are faulty. Carburetor rebuilders can fix these. I would also suggest you take apart the various components of the linkage and apply lithium grease to the swivel points.
In addition to Jay's recommendation check the hand throttle connection. Harry
Here is a picture of my Lasalle from today. Not finished yet. Dashboard and hand throttle cable not installed yet. Engine and carburetor rebuilt years ago. Car is drivable but doesn't get driven much. Seats 2024. Front doors built this spring. Hopefully back doors this fall. Looking for a bodyman/painter in Louisville Ky metro.
Tom,
Sent you an email.