Yanmar YSM Engine alternator questions

[NewbieNelson]

Hi All,

I bought a new alternator for my Yanmar YSM engine and have started to fit it, although looking through my manual I see the points on the diagram differant to the ones on the back of the alternator. The alternator has three places to connect wires to, Bat, E and P, but what do these mean? I am wondering if the alternator I bought is actually compatable with my engine? I am correct in my thinking, Red wire live is Bat, E is negative and P would be for charging lamp? I am a total noob with this engine but determined to learn so if I am completely off here then I humbley accept a verbal beating

Premier Gear PGEU-12109 Alternator Compatible With Yanmar Replaces VA-12109 AVF-12111 112270 10-12109 10-12111 28-1698 8EL726271-001 12109 12111

 

[garymalmgren]

Hi Nelson.
I take it you don't have the old alternator to use as a guide
On the original and according to the wiring diagram there are only 4 wires to the alternator.
There is no P connection.
The "Charging lamp" is the red that goes from the "T" shaped connector (on the alternator) to the Ignition switch.

Here is an original YSE wiring diagram (redrawn)

PS I just noticed that you have a YSM. Maybe this diagram is not relevant. But I will leave it just in case.
Gary

 

[VicS]

Hi Nelson.
I take it you don't have the old alternator to use as a guide
On the original and according to the wiring diagram there are only 4 wires to the alternator.
There is no P connection.
The "Charging lamp" is the red that goes from the "T" shaped connector (on the alternator) to the Ignition switch.

Here is an original YSE wiring diagram (redrawn)

PS I just noticed that you have a YSM. Maybe this diagram is not relevant. But I will leave it just in case.
Gary

Surely Gary's diagram shows that the warning light is the yellow connection to the T shaped connector. If this is marked it is the L terminal. The wiring schematic for YSM engines show this as a white/red wire but on more recent Yanmar engines it is colour coded blue/black

The red wire in Gary's diagram is a direct excitation connection from the ignition switch. This connection does not appear to exist in YSM engines but if the new alternator is reluctant to start charging it could be added. On more recent Yanmar engines this is colour coded red/black. When marked this connection is the R terminal

BAT is the battery positive connection

E is the earth or battery negative connection.

P, when it exists, is the tachometer signal connection ( Marked on other alternators and often referred to as the W connection ) YSM engines have a separate sensor for the tachometer

Wiring schematic for YSM engines attached

 

[Steve_N]

I fitted the same alternator to my YSE and as the others have said:
- ignore the P terminal and field connection
- light (red/white on mine) to L
- pos to BAT, neg to E

Although specified for clockwise rotation it does seem to run cool enough rotating counter-clockwise, as it does on these engines (pulley fan blades sucking instead of blowing, or perhaps the other way around?).