Force 120 HP mid range vibration.

[rsteiner]

I have a 1995 Force 120 HP outboard. I have a bad vibration from about 1500-2200 RPM. Engine starts good and runs good except at this engine speed (shakes the whole boat). Vibration exist in or out of gear. I placed a timming light on ignition wires and noticed that the #2 plug wire appears to fire at about half the rate as the other three. This was the case at all speeds. Engine seems to miss ignition occasionally but steady at the above RPM. What might cause this condition?? Thanks

 

[eurolarva]

Re: Force 120 HP mid range vibration.

I would guess this is an electrical problem but it would not hurt to test your compression first. If compression numbers are good you will need to follow the troubleshooting and ignition testing section in the manual. Here is a link for a manual Force Manual