1990 48HP not charging battery

[mechmagcn]

I just purchased a 1990 48HP and discovered that it is not charging the battery. I checked the fuse on the engine and it is good. What voltage should I read from the rectifier when the engine is at idle?
Thanks, Jeff

[faztbullet]

Hello Jeff, This is only a 10 amp system and that is @3500 rpm so at idle you will only get 1-3 amps depending on battery temp and age. Check your voltage before starting (ie:12.3vdc) and then start engine, if voltage is higher(ie:12.4-12.6vdc) and slowly increases with engine speed it is working. If not here is replacment part #581778 and how to test it...
Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier.

[mechmagcn]

Thanks, I was expecting a little higher voltage when running, so it could be charging. I'll do these tests if it ever quits raining and post back.
Jeff

[faztbullet]

At WOT you should see 12.8 or higher, anything higher than 14.0 needs battery and connection checked....

[mechmagcn]

Thanks, I'll try to check voltages this weekend.
Jeff