I have a newer system check tachometer which I would like to use on an older pre system check motor. The tachometer I would like to use is a 1996 and newer with the 8 pin connector. The boat and motor are both 1991. The tachometer is erratic , today I will be checking the grey pulse signal wire which I believe is working correctly. The batteries are charging also. My real question here is can I configure the new tachometer to work with the older engine. My thought is to use only the grey wire pin from the 8 pin connector. If the engine is sending a correct signal through the grey wire then it seems to me that the other system check functions if left unhooked should not interfere with the working of the tachometer itself. The current tach which is the original has the tighten down wire terminals. Blue(light), black(ground), purple (ignition) and grey(engine tach signal). The new system check tach has the eight pin connector and a light connection which I would be ground and blue.. The signal horn which is seperate and located, under the dash sounds for a second when the key is turned on.as it should. .
