Mercruiser alternator problem

[shelbylancer]

Working on a 1989 Sea Ray with the 7.4 mercruiser that has a Mando brand alternator. Last time out the voltmeter did not show any charge coming from the alternator, actually as engine speed increased the meter went down. The voltmeter never went above 12 volts and sometimes went as low as 8. The batteries were replaced at the middle of last season.<br /><br /> I am assuming the alternator is bad. Is there anything else other than the alternator itself to check? I have access to an automotive alternator bench tester but don't know how to hook it up to this style alternator. There are 2 screw/stud terminals which I believe are power and ground and then 2 wires coming out of what I believe to be the voltage regulator. Any thought on whether to replace the alternator or how to hook it to the bench tester? (friend works at Advance Auto, and can use theirs) Thanks for any help. Mike

 

[Don S]

Re: Mercruiser alternator problem

Belts

 

[shelbylancer]

Re: Mercruiser alternator problem

Belt is tight and all wires at the alternator are tight and not corroded. Pulled the alternator last night and will bench test it if I can figure out how to hook it to a tester.

 

[Bt Doctur]

Re: Mercruiser alternator problem

best thing to do is replace it with a 1 or 3 wire gm style alt.

 

[Don S]

Re: Mercruiser alternator problem

Take the alternator to a Starter/Alternator rebuild place and have them test it. All you need to do is test it wrong and your still at ground zero because you still don't know for sure if it's good, bad, or you tested wrong.

 

[shelbylancer]

Re: Mercruiser alternator problem

Thanks, I'll check around for a rebuilder that can check it.

 

[BigPoppaG]

Re: Mercruiser alternator problem

Originally posted by Bt Doctur:<br /> best thing to do is replace it with a 1 or 3 wire gm style alt.

What do you need to get it changed to a 1 or 3 style and how will this help him?