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alternator question...older 454's

realcaptron

Regular Contributor
Guys, I am well aware that we need marine approved alternators in our boats, but how do you visually know if an alternator is a marine unit if all labeling is gone? On my old (recently purchased) 32' Jeffries with twin 454 crusaders, the alternators are performing well but I'm just trying to ascertain if they are marine units. I found a label on one for a mfr I am unfamiliar with and model number. It is a "Leece Neville" model 8RG2043.....I believe 50amp and also has the number200045 on it. In searching the web, I found another boat owner forum with a topic post about this exact same model number, so I am assuming it is a marine rated alternator, but how do I know. (Please no humor about I'll know when it goes boom). If I can't get definitve, yes its a marine alternator, then i will of course replace and then investigate the other one too. Would rather not replace a good working unit if someone can assure me it is a marine alternator, or how I can determine. Thanks.
 
A marine rated product that needs to be shielded will "almost" always say "SAE J1171 Marine" some where on the product. It's usually either stamped or on a sticker. In the case of alternators, they usually have a enclosed tight mesh screen in the back as well. An online search for "marine alternator" will show you what I'm talking about.

Regards,
Duke1
 
The 8RG is the regulator part number and is for marine use as long as the gasket is used.....its probably an 8MR version of the alternator itself.

These wont have screens over the vents.....as DD suggested, the brushes are in a 'sealed' enclosure on the 8MRs.

Without the model number, I don't think anybody can say with certainty if what you have is appropriate....maybe a few pictures would help clarify...
 
The 8RG is the regulator part number and is for marine use as long as the gasket is used.....its probably an 8MR version of the alternator itself.

These wont have screens over the vents.....as DD suggested, the brushes are in a 'sealed' enclosure on the 8MRs.

Without the model number, I don't think anybody can say with certainty if what you have is appropriate....maybe a few pictures would help clarify...

Thanks, Mark....I will get a couple pics next time at boat. I'm kinda thinking these are marine alternators, but old. I'm a very cautious and respectful boater my whole life, but I also hate to replace good functioning units needlessly. Let me ask this also...with counter rotating inboards, does rotation matter to the alternator? Does my right handed (reverse rotation) starboard motor require a special alternator? I'm assuming the starter would be different due to cranking the motor in different direction?
 
electrically, the alternator doesn't care which way it spins.....mechanically (thermally), it needs a fan that will function based on the rotation....most have a bi-directional fan (using the rotor's axis for reference, the fan is a disk, bolted under the pulley, that has about a dozen or so "blades" under that disk).

The starter is basically the same, except for the drive...electrically, they get wired differently....
 
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