94 Volvo Penta 7.4 GL

llewis01

Petty Officer 3rd Class
Joined
Apr 7, 2012
Messages
75
Hello. I have a 94 albemarle with a 7.4. It is a GLIMDA model. My alternator stop charging and I want to replace it with a higher amp alternator. It now has a prestolite but I don't know what model number as the sticker is worn to where you can't read it. Albemarle shows it could be a 51,55 or 65 amp. I what to go to a 100 amp since we have a lot of electronics running. I would like to know what higher amp alternator would work that has the same hookup as my prestolite has which I think is a 5 wire. Thanks
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
50,426
your charge wire back to the battery will need to be increased. most alternators are a 3 wire installation, so depending on what alternator you obtain, you may need to re-wire
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,089
Take it to an alternator rebuild shop.
They can tell you what you had and f it's possible to upgrade and if not.
They'll sell you anything you need.
 

dypcdiver

Lieutenant Junior Grade
Joined
Nov 1, 2005
Messages
1,040
Something that you may not have though about, is the extra load on the "V" belt. I have recently helped a friend with a 100amp alternator on his yacht, which recharges the batteries when he has been under sail with auto pilot and fridges operating. He has been counting the number of hours a belt lasts rather than days. I was able to get a twin belt pulley made up for him, which matches the extra grooves on the other pulleys. As an aside his engine compartment is now black with belt dust.
 
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