Dregsz

I have a new tach and should probably call Fred at Trick w this question but I bounce it here first.

My tach reads fine to 4500 rpm but anything above that blows it apart and it reads 3300 unless I hit something electric, like a trim or tab button and then it reads true until I take my finger of the button.

This is w an OMC 300 V8 outboard application.

What is causing this?
Is it a problem w the ground?
THe voltage regulatoron the OB?
Is it a bad tach?

Thanks
Evan

BillK

Evan,
I have seen that problem several times in race cars and the solution has always been the ground connections. Are you using factory wiring or did you run new wires for the tach ? If it new, make sure the ground wire goes all the way to the engine block and make sure all the connections are clean, no paint etc. It could also be a tach compatibility problem, especially with the outboard. I am not familiar enough with outboard ignitions to know how they actually trigger the tach.
Hope this helps,