If it has a switch for 4-6-8 then you could try it set for an 8 cyl. That
would account for the 2 stroke having twice as many firing cycles as a 4
stroke.

"RB" wrote in message
. ..
Any reason I can't use a 4 cyl automotive tach for my 4 cyl o/b motor?
The
auto engine is 4 cycle, and the boat engine is 2 cycle.

I'm just wondering what it take to make it useable on the o/b.