60 HP Mariner charging problems

"HI,
I have a 1989 , 60 hp m

"HI,
I have a 1989 , 60 hp mariner that is charging at 17 - 18 volts. It has a new stator, the rectifier tests good. New batteries .... Help"

High charging voltage in a non

High charging voltage in a non regulated motor is usually caused by either bad or dirty connections or the wrong type battery installed. i.e. a car battery instead of deep cycle.

"Thansk for the info Ibnfishin

"Thansk for the info Ibnfishing, I installed a new marine deep cycle battery, but the problem was still there. I recently bought this boat and the work was done before I got it. So what I did is looked at the web page of the manufactor of the stator ( CDI Electronics) and read the installation manual of the stator. It says do not use a maintence free battery. The new battery I bought was a maintance free, so I went and took a battery out of my pontoon boat ( deep cycle maintance battery) and now every thing is working fine. Does anybody know the difference in the battery types?"

"Bill, as IBNFISHN eluded to,

"Bill, as IBNFISHN eluded to, Mercs charging system is "unregulated" on most of their motors.

Intead of a voltage regulator, they simply use a rectifier. It changes the AC produced by the charging windings on the stator into DC and uses the battery as the regulator/capacitor.

Because of that (somewhat unstable voltage) a (maintenance) battery has the ability to off gas if the electrolyte gets boiled a bit by wild voltages. And while that is not good for the battery and will definately reduce it's lifespan, that is infinately better than using a sealed (maintenance free) battery that's only option may be to "explode" if it can't handle all that unregulated power.

You just need to occasionally check your "maintenance" batteries and if the levels are getting a little low you can top them off with some distilled water and perhaps once a year you add a solution to balance them (sold under a variety of names) available at marine and automotive places..."