Well I think I know the answers now. I took apart the starter I knew was marine and the one stamped SAE marine, that I was unsure if it was really marine, or just a basturdized automotive. It's a basturdized automotive. The main difference between the two is the presence of a plate between the bendix throw out fork and the armature on the marine. I guess this keeps the sparks in. The marine also had ond rotted silicone that at one time was to seal the joints. The only other difference was the rubber bushing that, like said earlier, is probably to prevent arcing if something metal falls and hit it. Bottom line... I'm still one marine starter short. Anyone got one they want to sell?

Thanks to all of you for your assistance.

BT

I bought a rebuilt marine starter for one of my 7.4L last year for $65 from a local starter/alternator shop. For that, it doesn't make sense to put an automotive starter in it.

Blue Thunder Boat US sells all kinds of starters. I believe that I paid about 130 bucks for mine, new, no core charge. So far I am very happy with it. I believe it was the gear reduction one. If you have any questions let me know I have their Supliment catalog at the shop.

Jon

Thanks Audiofn... I'll have a look on the boat us bulletin board. If not, I may take you up on your offer... thanks.

BT

Years ago growing up around boats before bilge blowers were required, we were taught to ALWAYS open the engine hatch for a few minutes before starting the engine. Still do it today. It's extra insurance against going boom and it gives me a great excuse to show off my CMI's.

A proper marine starter is sealed at both ends,has rubber coated or (varnished) field coils,brass terminals(not copper) abd is painted inside as well as outside.If you look into the drive end housing,there should be a plate that carries a seal to seperate the bendix from the rest of the starter.There should be a rubber gasket between the solenoid and the housing and the solenoid cover should be gasketed as well.
Audio,if you can buy "new" gear reduction units for $130.00 USD,that is a deal.Mercury canada lists them for $370.00 here which equals $222.00 usd.

Auto starter + boat = BOOM!!!