17 volts okay for MCM 165?

natemoore

Master Chief Petty Officer
Joined
Jun 13, 2009
Messages
844
Mercruiser MCM 165, ser. no. B648337. I'm trying to troubleshoot dead battery problem. Seller said it happened to him a couple of times recently. I bought a brand new battery. It too went dead after a couple hours of motoring around the sound.

I measured around 17 volts at the battery at idle and 2000 rpm. Is that kosher? Too high? My SELOC manual is lacking in these kind of details.

Any other hints for why a new battery would go dead, besides the obvious (loose wiring or corrosion)?

BTW, before I drop another $80, is the Mercury #8 manual a lot better than the SELOC manual? I wasn't terribly impressed with it. I can do anything, practically, with a Haynes manual including remove and rebuild an engine, but I thought the SELOC glossed over things too much. Any opinions?
 

mkast

Lieutenant Commander
Joined
Nov 6, 2002
Messages
1,934
Re: 17 volts okay for MCM 165?

BTW, before I drop another $80, is the Mercury #8 manual a lot better than the SELOC manual? I wasn't terribly impressed with it. I can do anything, practically, with a Haynes manual including remove and rebuild an engine, but I thought the SELOC glossed over things too much.

The difference between the Mercruiser manual and the Seloc/Haynes is day and night. If you download the Mercruiser manual and read it, you'll see.
Time to check the voltage regulator.
 

180shabah

Rear Admiral
Joined
Mar 26, 2005
Messages
4,995
Re: 17 volts okay for MCM 165?

17 volts is WAY too high in any 12v vehicle.

Burn the SELOC before it burns you.
 

natemoore

Master Chief Petty Officer
Joined
Jun 13, 2009
Messages
844
Re: 17 volts okay for MCM 165?

Seloc manual doesn't appear to cover the factory alternator. Didn't see a single picture of the stator, rotor, or a single reference to a water cooled voltage regulator. It doesn't even have an index. I think the difference between this Seloc manual and a Haynes manual is night and day. The Mercury service manual must be like a summer solstice.

Since I'm loathe to tie up my computer all day downloading 355 MB, can anyone give the the quick and dirty diagnostics from their Mercruiser manual?

I have a diagram of it from the WAGDC-60 installation manual (which I'll probably wind up getting). Only down side is that my dog house is a too short for the add-on pulley.

I could buy the alternator from the kit (for $100), find/fabricate a double pulley to go on the power steering pump, and make my own bracket assembly. Alternately, I could theoretically use a serpentine-belt type arrangement and run everything on one belt. Anyone ever do this? It may just be easier to modify my dog house.

Last question: is it absolutely necessary to remove the stator? That would avoid me having to buy an expensive pusher tool (unless I could find a picture, then I could reverse engineer one).
 
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