1990 90hp Merc

[pz742q]

I am a little confussed. If the tach does not work and the battery is not charging. Do I have a rectifier problem or a voltage regulator problem?

 

[Silvertip]

Re: 1990 90hp Merc

I'm not a Merc expert but I think your engine has a regulator/rectifier -- in other words the two devices are not separate units. So to answer your question, you need to replace the regulator/rectifier. If by chance there is a separate rectifier, it can be checked with an ohm meter.