Alternator needed?

[rickturl]

I recently (yesterday) purchased a 1990 American Skier Volante. During the test ride we noticed that the engine was not charging the battery showing about 11.5V or so on the the voltmeter and virtually no current on the ammeter. This is consistent with us having to jump start the battery to test the boat!

I am not positive which Indmar engine I have. But all seem to use a 51 AMP alternator.

• Is there an easy way to determine which engine I have? (See attached S/N photo.)
• Does my alternator have an internal voltage regulator? The engine manual seems to imply that it does.
• Are there other tests I can/should perform?
• Where is the best place to get a new alternator/voltage regulator? How do I know which one to buy?

Thank you for all your help.

[rickturl]

Here is a picture of the engine if that helps identification.

[backfoot100]

Pull the alternator, take it to a starter/alternator repair shop and they can rebuild it. If they don't notice that it's a marine alternator, leave and find another shop.

[rickturl]

Turns out that a volt meter at the battery shows that the alternator is indeed charge with a voltage of about 14.2V. Now I just need to diagnose why the Alternator Warning Light is on and why the Voltmeter reads consistently below 12V even at 1800RPM and the ammeter does not show charging. But it seems I do not have a battery/charging issue in the short term at least.

[RonT]

If you are referring to the 2" engine warning indicator with lights and buzzer for low oil pres., high temp, low voltage, this stand alone parallel circuit gauge is non-adjustable and over time they have been notorious for going out of calibration and have been known to draw down other instruments, I would disconnect this and see what the voltmeter now says. (most of these have been disconnected permanently, the company that made them is long gone out of business. All newer boats use the engine ecm to do this function.