Scag Turf Tiger Project

[Robnjay]

This is my project:
Scag STT61-25CH
SN 431 1332


LOTS of problems:
Previous owner was mowing with it about 1 month ago and the bracket for the deck gearbox broke loose and the pulley on the gearbox was broken.
I am trying to approach the problems one at a time..

First thing is no start.
Kohler 25hp was replaced by a newer 25 hp Kohler - the engine electrical harness is not the old 3 wire harness and the conversion was not very clean. The engine is dated 2012 and this guy had replaced the carburetor and the starter. He said he was mowing with it when his disaster occurred.
So I would like to figure out how you should convert the 3 wire engine harness to a Kohler with a 4 wire plug:

 

[StarTech]

What is the current CH25 spec number?

 

[Robnjay]

What is the current CH25 spec number?

Still editing the original post - struggling with adding pictures

 

[Robnjay]

Still editing the original post - struggling with adding pictures

Don't know what "Spec Number" is.

 

[Robnjay]

Here's the wiring picture:


The existing Kohler engine. (Date is a little heart-warming, hour meter reads 3900 and change).

 

[StarTech]

Okay not a CH25. It is CH730-3225 with the 3225 being the spec number. It has a 15-20 Amp stator (alternator for you laymen). Carburated. CDI Ignition system. Does not appear to have oil pressure which explain only four wires.



This is the mower side wiring schematic.

 

[Robnjay]

Thanks!!
But the mower is:


So the engine harness from the mower has a 3 conductor plug:


Someone "converted" the 3 conductor to the 4 wire Kohler engine harness after replacing the engine..
I'm trying to understand how this should have been done...

My plan is to try and start or turn over the engine.
I'm going to proceed with rebuilding the deck before I go much further with the mower itself...