How are Marine altenators different from Auto altenators?

Question

We have an old ski boat and are having some minor motor issues. We put an alternator bought at an automotive store instead of a marine alternator out of Overton's cataloge. We are just wondering what the difference between a marine alternator and an alternator for a vehicle would be.

Answer 1

What you have done is EXTREMELY dangerous. The correct alternator has a screen on the back to prevent explosions and fire. Replace it before you become a statistic. I recommend an AC Delco one wire MARINE alternator for simple installation, around $100

Answer 2

a marine alternator has corrosion resistant parts and most of all are spark resistant to keep from possibly blowing up your boat in the event that gas fumes accumulates in the bilge...

Answer 3

A marine alt is designed to not produce a spark when running> Diesels can use auto alts>

Gas engine must use marine alt or you run the risk of an explosion and fire>

Answer 4

Same thing, Different manufactures us different alternators. Most alternators are 12 volt although some are 24 volt but as far as there job they all do the same thing. They may have a coting on them to prevent corrosion but all the ones I've replaced came from a car alternator shop.

Answer 5

Just FYI, it is actually illegal to run an inboard or inboard/ outboard engine with with a non-marine starter or alternator. You must also have a spark arrestor on the carb.

It's really unlikely that anyone other than the coast guard would shut you down for it though.

The answer that says anti corrosive parts and spark arrestor is the correct answer to your question.

Answer 6

The difference is its "explosion proof". Marine alternators have USCG stamped on them. Replace your automobile one with a marine one. It may cost a little more now but dont take the chance to spend tons more later if it does cause an explosion.