hey Jimmbo,
I had this problem for the last 2 years. I have spark to all 4 piston. 118, 118, 120, 120 compression on the 4 cylinders.
My overtemp horn works, I did not check the thermostats. I replaced the power pack Sept. Of 2020. I also rebuilt all 4 carburetors Sept. 2020.
I rebuilt the vro...