The timing of this motor is 19° before top dead center and when I checked it The timing was off considerably. I set the timing at 15° before top dead center. My original problem was that the engine does not idle smoothly so now I’m thinking that something is not up to par electronically although I do have a good spark at 7/16 of an inch. I Purchased this engine used and it has always ran fine upper end but rough on the low end so I ran a compression check cylinders are within two PSI of one another compression is 130 cylinder number one/128 psi on cylinder number two I believe it was 150 psi new. I’ve clean the carburetors reset the linkage to spec rebuilt the VRO pump and of course new plugs.