On May 21, 6:17*am, tem wrote:
I have 1986 Mercruiser 170 (mdl MCM 170) w/ 2 battery system. This may
be a dumb question, I'm not a mechanic. My volt meter reads 12.3 on each
battery when engine is not running and 12.2 after I started it. Does
this mean my charging system is not working? Any help or advice is
appreciated.

--
tem

If I remember correctly the 170's (also 470's) had a low amp stator
mounted behind the harmonic balancer, that would eventually give out
and cause a lot of grief. I've seen somebody on evil-bay offe3r a
conversion 'kit' which consisted of a marin-ized , internally
regulated 10-SI delco alternator and the appropriately made brackets
to hang the alternator on the engine and run via a belt, but they're
pricy, like in the $3-400.00 range. But then again, this would provide
much better reliability, 65 amps (+/-) of power and easy service if
necessary.

You might wish to check out this thread as well:

http://www.marineengine.com/boat-for...harging-system