1975 225 omc one wire alternator conversion

[Seabee75]

Hey folks, been lurking here for a long time. Finally decided to create a profile and start posting.

Well, I have a 1975 24' Reinell flybridge cabin boat with a 225 horse omc.

Since I bought the boat a few months ago, the charging system has slowly dwindled. At this point, testing from the rear of the alternator I am putting out about 12.4 volts.

The alternator is a prestolite 45-55 amp I believe, externally regulated. I am thinking I want to convert it to a 10si delco internally regulated. I have found a few online in the 100 amp range for under $120 shipped. I believe just from eyeballing it should have the same bolt pattern, but if not I am sure I can rebuild the mounting bracket to accomodate.

The question is has anyone done this? Again the motor is a 225 horse 307. I priced the regulator at $76 and the alternator at 275-350 for another 55 amp, which does not really interest me. Im thinking money better spent to upgrade and simplify.

Thanks in advance for any insight.

 

[cr2k]

Re: 1975 225 omc one wire alternator conversion

You MUST make sure it is certified for MARINE use, other wise your boat could go Boom!

 

[rotaryboots]

Re: 1975 225 omc one wire alternator conversion

It definately can be done, I did it to mine because the stock one doesn't put out nearly enough amps for what I'm running on mine. I used one off a 5.7L Chevy engine from a mercruiser at a boat yard. This alternator was actually a two wire because one ran to the battery, and the other ran to an "alt" light. Another thing, it bolted right up to the stock brakets.