Odd engine behavior after first shutdown of the day

[cycleguy55]

Originally Posted by MaSnaka

In addition to what everyone else said I recently found my primary plates were catching at idle. Causing my idle to hang up while the rumble of the engine would shake it back down. I loosened the screws just enough (careful not to let one fall) so the plates could move and find a new happy place on the pivot shaft. Sure made a difference when slowly easing into the gas for 1st gear starts. It could be a little twitchy before.

Before I discovered this I thought my pedal or cable was binding but could not find any faults. I did spray some WD on the advance weights in the dist. too.

Good luck.

John

I can understand that - and how it may apply here. The carburetor body and the throttle plates expand as they warm, but the airflow of a running engine mitigates that. When a hot engine is then shut off the airflow stops and the heat soak allows the carburetor body and throttle plates to expand, creating an interference fit if the throttle plates aren't perfectly positioned. Re-positioning them eliminates the interference. Brilliant!