Yanmar Alternator Upgrade

[Jon4399]

The alternator on my Yanmar 3HM died recently, and in replacing it I came up with a Delco CS130 Series with a 105A output. The new one physicallly fits on the engine and the belt lines up. The alternator is interlally regulated, and is called a one-wire system. Apparently I only need to connect the Batt output and everything will work. The concern I have is that the Yanmar wiring includes two additional wires which went to a plug on the old alternator. One of these was to the ignition, and the other to the alternator lamp. With a one-wire alternator, will the sounder alarm go off because the other wires are not connected? The new alternator includes a rectangular plug with 4 pins. The source says these need not be used. Any thoughts?

[Chief Engineer]

Why are you changing the electrical system?

[GordMay]

The CS-130 should have a 4-wire plug, in addition the Battery lug.
The plug identifies the individual wires by the following letters (S F L P) usually marked on the side of the plug:
(S) is the sense wire. This is connected directly to the battery.
(F) is connected internally to field positive and can be used as a fault indicator.
(L) is connected to a charge indicator light, or to a resistor, or to both.
(P) is connected to the stator and can be connected externally to a tachometer or other device.

[Jon4399]

Thanks Gord. I have that info already, but have been told by many that I need not connect any of these for the alternator to work properly. So the question is, "What will happen if I use a plug and wire the the existing sense (lamp) and ignition (Sense) wires?" Or can I simply tie off these and let the alternator do its thing.

[Jon4399]

Originally Posted by Chief Engineer

Why are you changing the electrical system?

Replacement alternator for Yanmar (35A) about $350.00. Delco (105A) about $125.00. Seemed like a good idea at the time.

[fairbank56]

Secure the old plug out of the way. The lamp will not come on.

Eric

[Florida Mike]

You might consider the size of your original output wire with a higher amp alternator. The extra current may overheat the existing wires. The 35 amp alternator puts out about 455 Watts, whereas the 105 amp alternator puts out about 1365 Watts. If it were mine I would parallel any number 6 or 8 wire with the original. Just my two cents, Mike.

[Jon4399]

Thanks Mike. I have already considered doubling up the output wire from the alternator. Don't want to fry the original.