How can I tell if starter and alternator are marine?

[boatdude100]

Bought boat with Mercruiser engine swapped from s10 "old truck

Apparantly a car starter and alternator can blow up boat?
How can I tell if they are both marine from the old engine or swapped from Mercruiser (alpha one)?

 

[fhhuber]

Should have the maker's plate that says it is a marine part.

The danger is if there is a spark in the engine compartment while there are fuel vapors present.
Fuel fumes in the bilge essentially makes the boat into a bomb waiting to go off.
Marine rated electrical parts are much less likely to produce a spark.

 

[tpenfield]

"SAE J1171 Marine" would be the sticker that you are looking for. You could also get a part number off of the starter & alternator and then google them to see.

On my 24 footer, there happened to be an automotive starter, which I was unaware of, until I replaced it. It had a GM part number, which I could not cross reference to a marine part.