Merc Alternator trouble?

[tdulick]

The volt meter on the boat reports varying voltage from 10 volts to about 13, but not related to rpm's. Is this a sign the alternator is starting to fail and shold be replaced? Is there a voltage regulator on the boat?

 

[Don S]

Re: Merc Alternator trouble?

There is a voltage regulator, but it's usually built into the alternator. (Depending on make, model alternator)
It sounds like you may just have a loose V-belt on the alternator maybe rusty pulleys eating the belt up?

 

[tommays]

Re: Merc Alternator trouble?

Not a lot of info there


But the alt output should be checked with a hand held meter(DVM) at the battery

It should be in the 13.5 to 14 volt range when the motor is running depending on the batterys current condition

Tommays

 

[tdulick]

Re: Merc Alternator trouble?

Thanks for the assistance = The belts are good, and tightened properly, and there is no rust in the engine =compartment - the boat is a 1996, so 11 years old now, so could the brushed in the alternator be wearing out?

 

[Haut Medoc]

Re: Merc Alternator trouble?

I'd check the wire connections......
You could pull it out & have it bench tested.....​

 

[Don S]

Re: Merc Alternator trouble?

If all your connections are good, pull the alternator and take it to a starter & alternator repair shop or even many NAPA and other parts stores and have it tested.
They can put a load on it and see if it's working properly.

 

[tdulick]

Re: Merc Alternator trouble?

Thanks for the suggestions - I am guessing I can get a meter to check it without taking it out? Any ideas on what kind of meter I need and what they cost?

 

[180shabah]

Re: Merc Alternator trouble?

A cheap DVM will only set you back about $10 at radio shack.

Take a voltage reading at the batttery
Should be 12.8ish

Start the engine and take another reading while it is running at fast idle
Should be 13.5 -14

 

[tdulick]

Re: Merc Alternator trouble?

Thanks for the assistance