single cylinder?
gee
never seen one of those in a tennant before
Must be made alot like most single cylinder motors like the briggs and Tecumseh engines?
Could be a problem in the reluctor pickup (if it has one of those)
Most of these type engines do have some type of generator component to generate the spark timing on the flywheel to tell it when to spark.
I'm not too familar with these robin engines though.
Can you get any information on this engine from tennant?
I'll see what i can find if you can get the engine number off the engine.