'95 Mariner Magnum 150 not charging cranking battery

mknaron · #1 January 19th, 2004, 04:19 AM

I have a '95 150hp Mariner Magnum, EFI, it seems that my motor is discharging my cranking battery.

When the engine is off the in-dash volt meter reads about 11 volts, first thing in the morning. But, when I am running the voltmeter drops to about 10 volts. shouldn't it be around 14 volts when running? My battery will usually get to week to crank the engine after about 6 hours on the water. How can I check the output of the engine charging system?

Trent · #2 January 19th, 2004, 05:48 AM

First off.......Do you have a tach? Is it working correctly? Tachs usually show up first when the charging system has problems. The tach is connected electrically to the charging system. First check the connection on your voltage regulator. Item #7 web page You will need a manual to get more into depth on troubleshooting. I bet its the regulator but you need to test first.

mknaron · #3 January 19th, 2004, 06:21 AM

Thanks for the reply.

Yes,the tach is working fine. I'm going to pick up a manual today. If it is the voltage regulator, would that make the engine run bad or anything?

mknaron · #4 January 28th, 2004, 03:12 AM

Thanks Trent.

It was definetly the regulator/rectifiers. Both of them were fried. I replaced them yesterday and tried it out. I'm getting 14.5 volts at the battery now, with the engine running.

...thanks again.