Yanmar 55Amp alternator

[r shelby]

I'm trying to upgrade the 35A alternator my old Yanmar 3QM30H with a new 55A Hitachi from a 4JH2 76HP, But I can't figure out the different wiring harness. Could someone possibly send me a schematic of the alternator circuit for the 55Amp alternator? The E and the B terminals are clearly labeled, but there is a third unlabled terminal, as well as a male T-plug (Tachometer?).Both alternators have IC regulators, and the cases and pulleys fit OK. I don't have a tach, but I do have a simple Idiot light. ("L" on the 35 amp alternator) Thanks in advance,RS

 

[Ed Schenck]

Hitachi 55Amp

I hope we can sort this out because I have a 55 amp alternator in my basement and a 35 amp on the Yanmar. The attached photo is from the Yanmar manual and matches our current 35amp setup. The manual is at home and has both alternators in it so I will check tonight. And I plan to be at the boat on Wednesday and will take some notes. But as you can see from the picture only 'E' and 'B' have anything to do with charging. My 2QM20 does have a tachometer so will be a little different from yours.The picture(50K) would not load but it shows 'E' to ground, 'B' to battery, and 'L' to light. I also plan to have mine tested at the local auto electric shop. They can tell me what that blank post is for.

 

[Ray Bunkofske]

Hitachi Alternator "T" connector

The "T" connector (at least for the 35 amp alternator) is:Top of "T" is the 12V from the ignition switch so that the internal regulator knows to "turn on", the vertical plug is an idiot light back to the panel to tell you the battery is charging.I'm also replacing my 35A alternator, but decided to go with an AmpTech. Based upon new prices from Mack Boring it has more power and costs less even considering the external regulator.