1979 MD7A Alternator Replacement - SailNet Community
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post #1 of 3 Old 04-25-2013 Thread Starter
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1979 MD7A Alternator Replacement

Has anyone replaced the alternator on the MD7A? I need info on a replacement, if so. The current (original) alternator is a sev marchal 70229702, 35 amp, 12 volt. I would rather not try and find another original (freaking expensive) alternator, but a newer, more efficient model. Another reason is because I replaced the tach and need an alternator with a "W" connection to power it. See my other posts for info about that aggravation. :-)

Seems it is more difficult than just going to an alternator website and plugging in the info. The original has a 5" pulley, which gives an approximate 2.5 drive to alternator ratio, which is the ratio needed. All the newer models have 2 and 3 inch pulleys, which are too small for the drive wheel. It spins the alternator too fast. Also, the newer alternators have a 17 mm shaft, and my original is a 15 mm shaft, so no swapping the pulleys.

I know someone out there has had to replace theirs....anyone?

Thanks in advance for any helpful information.

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post #2 of 3 Old 04-27-2013
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Re: 1979 MD7A Alternator Replacement

Spider Marine lists several alternators for your engine. Here's one.

New Paris Rhone 12v 60 Amp Volvo Penta Alternator: Alternators &amp Alternator

You could call them to ask about the pulley size options.
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post #3 of 3 Old 04-29-2013
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Re: 1979 MD7A Alternator Replacement

ARCO Marine also lists the alternator...Volvo part # 841765 (the 50 amp version) cross references to ARCO part # 80108....and again. you may have to talk to them about the pulley size. I have a 78 MD7A and haven't had to replace mine YET.
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