Power problem - 1999 200HP Merc EFI

Hey guys,

I've been having problems recently with my cranking battery (at least I thought it was my battery)... I replaced it twice and I'm still having problems. I'm thinking it might not get any charge from the motor. Also, I noticed that when I'm driving and I hit the trim (up or down) my voltage (and power) go down... same thing for when I turn on my pumps or units (or anything connected to my cranking battery for that matter). Also, when my battery is completely dead and I manage to start the motor, I don't have all the power I usually have. I thought a running motor didn't need battery to operate so I'm a bit confused.

I was told it could be either my voltage regulators or my stator.

Any ideas?

Thanks

Sounds like either or both the regulators or stator... There are a few tests that can be done (CDI electronics page has some decent troubleshooting/testing information) but the easiest is the visual test... look at each of the coils on the stator, are they off color from the rest/burned/melted? Secondly, check the connections at your regulators, specifically the red/yellow... are the bullets burnt/melted/discolored? then you can check the regulators themselves... any melting/swelling? chances are you fried some or all of those parts... i'm told to replace the regulators in pairs, even if one looks ok. I have a forum on here with bad regulator/stator test recently that explains the hell I went through searching for my problem and my results.

I'd recommend STARTING with a load test of your battery to confirm it's ACTUAL capacity and condition.

Verify battery terminal connections are CLEAN, ENGINE CABLE INSTALLED FIRST, remaining lugs largest to smallest, and finish off the connections with a STAINLESS LOCKNUT (do NOT use wing nuts).

Then test voltage AT THE BATTERY:

-Before starting engine
-After running for 5 minutes (with engine running).

Inspect voltage regulators at back of the engine (under coil plate)... look for any burnt spots, browned/blackened/burnt connectors, etc. IF ANY OF THESE ARE NOTED- REPLACE BOTH regulators with new OEM units, and replace any damaged bullet connectors.

Also wise to inspect/test stator (visual inspection for discolored, burnt, or melted "bobbins").