20 hp Kohler no spark

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Fish-N-Fool

Forum Newbie
I just purchased a Scott riding lawn mower made by John Deer It has a Kohler 20 hp 624 cc twin cylinder motor. It was running fine when I got it but needed a battery. It had a broken wire that ran to the key that I had to hot wire to get it to start. It would start when I jumped it but had no juice on its own. It died one day trying to move it and I couldn't get it to start So I thought I would figure it out after I bought a new battery. So got my new battery today and figured out it now has no spark. I fixed the broken wire and that works as it should but no start. Any clues what would cause it to lose spark to both cylinders at the same time?
 

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HERE IS THE WIRING DIAGRAM
WIRING HARNESS John Deere Parts scheme diagram



Parts on group WIRING HARNESS:​


Pos.Part NoQtyParts nameComments
1. [1] Connector HOUR METER
2. [1] Connector IGNITION SWITCH
3. [1] Connector
4.

[1] Switch RIO LATCH
5. [2] Connector RIO LATCH SWITCH
6.

[1] Connector BRAKE SWITCH
7.

[1] Switch BRAKE
8.

[1] Rotary Switch IGNITION
9.

[1] Key (SUB FOR AM123426 OR AM131946)
10.

[2] Nut 5/16"
11.

[1] Solenoid
12.

[2] Screw M6 X 12
13. [2] Connector SOLENOID
14. [1] Connector (REAR TO FRONT HARNESS)
15. [1] Connector
16.

[1] Wiring Harness REAR, (SUB FOR GY20166)
17. [1] Connector HEADLIGHT
18. [1] Connector
19. [1] Connector SEAT SWITCH
20.

[1] Switch SEAT
21.

[3] Clip (SUB FOR M124687)
22. [1] Connector (FRONT TO REAR HARNESS)
23. [1] Connector ENGINE
24.

[1] Relay
25.

[1] Plug
26. [1] Connector RELAY
27. [1] Connector
28. [1] Fuse Holder (INCLUDES 20 AMP FUSE)
29.

[1] Wiring Harness FRONT, (SUB FOR GY20165)
30. [2] Connector ACC POWER PORT
31.

[1] Socket Outlet 12V W/COVER (INCLUDES NUT)
32.

[1] Switch PTO, (SUB FOR AM119139)
33.

[1] Elec. Connector Terminal PTO SWITCH
34. [1] Clip
35.

[1] Hour Meter
36.
[1] Switch
 

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On the side of the engine should be a Kohler ID tag with the model of the engine , year of manufacture
This is important because Kohler used a couple of different ignition systems on this series of engines
If it has the SAM controller then that requires power to it or you will get no spark
If it does not have the SAM module then it will have a std ground to kill wire. s2048.jpg
 
bertsmobile1 said:
On the side of the engine should be a Kohler ID tag with the model of the engine , year of manufacture
This is important because Kohler used a couple of different ignition systems on this series of engines
If it has the SAM controller then that requires power to it or you will get no spark
If it does not have the SAM module then it will have a std ground to kill wire. View attachment 67320
Click to expand...
According to the tag, which is in my first post above, it is a model CV20S. I don't know what a SAM controller is, so I have no clue if it has power or not.
 
Fish-N-Fool said:
According to the tag, which is in my first post above, it is a model CV20S. I don't know what a SAM controller is, so I have no clue if it has power or not.
Click to expand...
SAM=Spark Advance Module. Unique to some Kohler engines. You will need to follow the wiring diagram and wiring on mower to track down the problem. Use a multimeter and test light.
 
So I got a few things figured out, It has mags on it, not the SAM. I disconnected the white wire to the coils, and it has spark and ran. So now that I know that I put it all back together with the wires back on, and I just have to know where it is switched to turn the spark on and off. Would it be in the key switch or maybe something else?
 

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I posted the wiring diagram some time ago
Follow the white wires
Note there are several circuits that run in parallel
If any one of them goes to ground then you get no spark
 
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