Boat never had a tach. Motor and control box were installed at a later date. My OMC has a plug for a tach harness on my other boat. I was hoping Mercury had something similar.should be a gray wire under tha dash.. tha other end should be plugged into a gray wire on one of tha rec/reg..... thats tha "signal" circuit... did tha boat not come with a tach or are you jus now adding one?
92 2.5 offshoretha merc stuff should have it!... what harness and controls are ya workin' with?.. motor year?