I have a 1998 50hp Johnson and every time I go to start the engine the "check engine" light comes on and the horn sounded for 10 seconds. The check enin alarm is suppose to be for fuel restrictions but I checked my manual and for this model and it doesn't use the check engine senor. It only uses the low oil, no oil, and overheating sensors. I checked for a short in the system and couldn't find anything. Is there away to test the tach? Or is there away to test which wire is setting off the alarm and bypass it?