Tach help??

[aka_therebel]

I swapped motors on my V-mate and swapped the tach with the one out of the boat the motor came off of. The tach works but isnt reading right, when on the water at WOT it only reads about 1500 RPMs. I have gone through all the wireing rechecked everything several time. Does anyone have any ideas?

 

[groundloop]

So the tach and engine you have now were together on another boat, correct? Did that tach work properly then?

You may have already checked this, but be sure your engine's charging system is working. One of the main causes of tach problems is a bad rectifier (or more often than not, a malfunctioning tach is a common sign of a bad rectifier).

 

[aka_therebel]

Yes the motor and tach are both from another (the same) boat. Im not sure if it worked on the other boat I never ran it on the water so I only witness it at an idle. Im not sure about the charging system, not even sure how to check it.

 

[groundloop]

OK, my money's on the rectifier. For mine I'd have to disconnect all three wires from the rectifier, then check forward and reverse continuity between yellow/gray and ground, between yellow and ground, between yellow/gray and red, and between yellow and red. Each of these checks should show continuity in one direction and not the other.

It would really be a good idea to get a factory service manual for your engine. I've got both the actual factory manual and a more generic one from Clymer, and the generic manuals pretty much suck.

 

[aka_therebel]

I do need to get a manual thats for sure. I will try to test it and see what I get. Thanks for your help!