Kohler SV735 DSAM Bad??

[Turbodriven]

The short video attached should explain it better than I can.

Essentially I'm not getting 12v to my fuel shutoff solenoid unless I unplug the 12 volt lead to my DSAM.

One thing to note in addition to what I mentioned in the video about unplugging the other leads to see if anything changed, is that I've continuity checked the 12 volt source to the d-sam with all the 6 other leads and I'm not getting any registered shorts.

 

[VegetiveSteam]

With everything plugged is as it would normally be, do you get any spark when cranking the engine over? I doubt there is anything wrong with the DSAM. I think you have a supply voltage issue. With the DSAM unplugged you're measuring voltage that isn't being asked to do any work. When you plug the DSAM in, you're now creating a draw making that voltage try to do work. Unplug the DSAM and fuel solenoid and use a fused jumper wire to power both of those components directly from the positive terminal of the battery and see if everything works correctly. If it does, then you need to see why voltage would be dropping on the wiring going to the DSAM and fuel solenoid.

 

[Turbodriven]

With everything plugged is as it would normally be, do you get any spark when cranking the engine over? I doubt there is anything wrong with the DSAM. I think you have a supply voltage issue. With the DSAM unplugged you're measuring voltage that isn't being asked to do any work. When you plug the DSAM in, you're now creating a draw making that voltage try to do work. Unplug the DSAM and fuel solenoid and use a fused jumper wire to power both of those components directly from the positive terminal of the battery and see if everything works correctly. If it does, then you need to see why voltage would be dropping on the wiring going to the DSAM and fuel solenoid.

Yeah good point. If feels like the source of the issue is the DSAM since when disconnected the voltage shows right. But maybe it's simply the normal load of the DSAM that is overpowering the system from a separate issue. When this was on the mower I checked spark on both cylinders and I was getting spark. I can check again though.

But first I'm going to do what you suggested by disconnecting the harness altogether. The harness to the motor is only four wires. A 12v to the fuel shutoff, a 12v to the DSAM, the white ignition kill which is ungrounded during running, and the purple charging wire. Technically all I need is the two 12v sources I think, with the white wire ready to ground.

For what it's worth, the battery is good. It was used to crank the motor off and on for a good 10 minutes from a full charge with no issues.

 

[Rivets]

Maybe the wiring diagram in this manual will help you out. https://resources.kohler.com/power/...9.1090484172.1709579829-1886006271.1709579829

 

[Turbodriven]

Maybe the wiring diagram in this manual will help you out. https://resources.kohler.com/power/...9.1090484172.1709579829-1886006271.1709579829

Yep, thanks. I've got it on my bookmarks already. Invaluable with these motors.

 

[StarTech]

Bad or loose connections.

 

[Turbodriven]

Bad or loose connections

I don't think this is the issue. I've triple cleaned the main engine harness plug and it looks good. However the rest of the harness is complex and just laying all over the workbench. So it's possible there are deeper issues involved in the harness as a whole. I'll be removing the harness later and testing without it.

 

[Turbodriven]

Follow up post.

I disconnected the main harness and direct connected 12v to the DSAM and the Solenoid. Motor fired right up with no issues. Revs up and down (no load) easily. Must be something in the main harness. Luckily I don't need that. To the trash can it goes. This is just a spare motor I picked up for my other mower.

The bigger issue now is that I'm getting uneven compression readings. Around 140psi on #1 and 180psi on #2. Not ideal. I'd feel better if it was both 140 to be honest. Opinions welcome...

 

[Tiger Small Engine]

Follow up post.

I disconnected the main harness and direct connected 12v to the DSAM and the Solenoid. Motor fired right up with no issues. Revs up and down (no load) easily. Must be something in the main harness. Luckily I don't need that. To the trash can it goes. This is just a spare motor I picked up for my other mower.

The bigger issue now is that I'm getting uneven compression readings. Around 140psi on #1 and 180psi on #2. Not ideal. I'd feel better if it was both 140 to be honest. Opinions welcome...

A ten percent differential between cylinders is what you are looking for as acceptable. I would check the valve clearance as a first step. Could be worn rings, partially blown head gasket, etc.

 

[StarTech]

Just throwing money away. I would have repaired the harness and eBayed it if I didn't need it. Lots people looking to replace their damaged harnesses.