Yanmar 1GM10 alternator

A

anpgr

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Hi All,

Could you please recommend alternators that would fit a 1996 Yanmar 1GM without any modifications? Any car alternators that would do? My current alternator is the original Hitachi 35amp (part no. LR135-126) but it is faulty and the repair shop asked for £100. I'm not looking for something bigger although I wouldn't mind going up to 55amp..

Many Thanks
A.
 
There are two main issues.
1) The 'foot' fitting of the alternator.
2) Space in the engine box

FWIW I fitted a Mondeo Bosch alternator from a car scrapyard to a 3GM30F. To do so I had to saw about 4mm off the yanmar alternator bracket at the front, in order to get the pulleys to line up. The single vee pulley came from a vauxhall viva IIRC.

Basically I went to a car breakers where they let me look over a huge stack of alternators until I found one that would do.
Cost £20 plus £3 for the pulley few years ago.

The tensioner stay can be ad-libbed within reason, I may have moved it to a different point on the engine.

Very worthwhile, the low speed charging was much improved!
 
You only have less than 8hp to play with at max revs and just about nothing at start up.. Fitting a bigger alternator, leaving aside the difficulty of finding one to fit, will cause serious starting problems. The 1GM when it has a saildrive (which adds more drag) has a cut out to disconnect the alternator for starting.

£100 to fix it is a bargain. New ones are probably 3 times that.
 
Fair comment about the lack of power, but can be got around.

What's wrong with the old alt?
Is it mechanically sound?
Brushes, regulator and rectifiers can all be substituted with generic parts for 2/6d.

£100 to fix something is not a bargain if it breaks again within a year or three.
Even 7HP is a lot of amps from a 12V alternator 740W=12HP roughly?
That's around 40A/HP.
Don't fit too small a pulley on the alt and it will probably be ok. If there are still problems, fit a resistor in one brush lead to reduce the rotor drive.

For £100 I would be wanting a warranty, but a warrany isn't much help at sea either.
I sold my original alt on ebay when I upgraded, maybe one will turn up?
It's nice to either have a spare in the garage or knowthat I can get one from the scrappy any day of the week, rather than being committed to an obscure and aging unit.
YMMV!
 
Thank you all for the advice. Just to note, the engine is a 1GM10. In any case I do not intend to fit a larger alternator, although looking at car alternators they all seem to have quite higher output than 35amps. I've found similar to mine 2nd hand alt's on ebay for around £120 but thought I could get away with spending much less if I bought a car alt'r as I've just spend ££££ on some other boat repair and I've gone a bit stingy now..

I thought about replacing the faulty part myself but I don't know exactly what the fault is - although I suspect it's a blown diode in which case I guess I'd have to replace them or get a new rectifier. Is this an easy job to do? Has anyone done it? Do you know the part number and where to get it from?

Many thanks again.
A.
 
Tranona said:
Even more reason to get the old one repaired.
Click to expand...

That may depend on urgency and availability. I bought a pattern one from eBay, and plan to replace the gradually-seizing bearings on the original Hitachi myself when I have time, then keep it as spare. That was the plan for the starter, too, until I found a nearly-as-good-as-new OEM one on eBay...
 
R32Stbrigid said:
I believe the alternator from a Renault 19 is a direct fit ......
Click to expand...

If that's correct get yourself down the scrappie, although there might be issues with pulley size to be overcome.

Even 7HP is a lot of amps from a 12V alternator 740W=12HP roughly?
Click to expand...

I hate to be a pedant but for the sake of anyone reading this that isn't aware, that should read 740W=1HP (not 12 HP - presumeably an innocent typo)
 
Give Superstart a ring on 01243 379865. They did me a replacement for my 1GM10 after discovedring a fault on day of summer cruise, had a replacement on the shelf (from what I remember about £120). Also great with advice and checking for faults/repairs.
Happy sailing
 
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