Kohler SV840 no spark

L

LawnWizard

Well-Known Member
Troubleshooting a no spark issue. Engine spins over. No spark. Both coils test good, checked for sheared crankshaft key, tried a known good voltage reg / rectifier, new plugs. One thing that I do NOT know on Bad Boy / Kohler is which (if any) safety switch will allow the engine to crank but cut off the electric to coils etc? Likely causes for no spark? Ign switch? Relay? Any suggestions are much appreciated.
 
Highly unlikely you were able to test the coils properly, as you need expensive equipment to do so. Retest the coils this way. Hopefully you have only one kill wire attached to the coil. If you do proceed as follows. Remove the shroud, disconnect the kill wire from the coils, If one or both plugs spark, coils are good. If they don’t spark bad coil. This is how the good techs do it with these Hall Effect coils.
If you have 2 or 3 wires attached to the coil you will have to refer to the testing procedures in this service manual. https://resources.kohler.com/power/kohler/enginesUS/pdf/32_690_01_EN.pdf
 
Rivets said:
Highly unlikely you were able to test the coils properly, as you need expensive equipment to do so. Retest the coils this way. Hopefully you have only one kill wire attached to the coil. If you do proceed as follows. Remove the shroud, disconnect the kill wire from the coils, If one or both plugs spark, coils are good. If they don’t spark bad coil. This is how the good techs do it with these Hall Effect coils.
If you have 2 or 3 wires attached to the coil you will have to refer to the testing procedures in this service manual. https://resources.kohler.com/power/kohler/enginesUS/pdf/32_690_01_EN.pdf
Click to expand...
Thanks for the info. Now, as weird as this sounds, I have good spark with the kill wire removed (only 1 each) BUT now I also have spark with it attached. On both coils. And still no start.
Additional info: my buddy says he replaced head gaskets sometime last summer and it ran fine but he says he "really doesn't know how to set the valves properly". Since I have spark, air and fuel, the only thing left is compression on the engine side. That's what made me check the crank key. Seems like it would still try to run (at least on one cyl.) Yes?
So I go back to something electrical other that coils, spark, etc.
Also, I just put on a new starter. Old one was hanging up in the flywheel.
One more thing, when removing the coils to pull the flywheel, I see where both bolts on bank 1 were stripped and it appears one side may have been rubbing the magnet.
I know this is a lot to digest. Thanks for taking the time to sort through it.
 
Couple of things to check. Is your engine equipped with a fuel solenoid on the carb? If it does grab the solenoid with one hand and turn the key to the run position. You should feel and/or hear the solenoid click. This will indicate that it is working. If nothing the plunger is stuck and you’ll have have to remove the solenoid and clean it with carb cleaner until it moves freely. Rretest. Also now having spark with the kill wire attached, I would be looking for a fray or crimp which will cause an intermittent kill situation, loosing spark. I would also recheck the magneto air gap on both coils and set them to .010”. Adjusting valves is covered in the manual I attached.
 
Rivets said:
Couple of things to check. Is your engine equipped with a fuel solenoid on the carb? If it does grab the solenoid with one hand and turn the key to the run position. You should feel and/or hear the solenoid click. This will indicate that it is working. If nothing the plunger is stuck and you’ll have have to remove the solenoid and clean it with carb cleaner until it moves freely. Rretest. Also now having spark with the kill wire attached, I would be looking for a fray or crimp which will cause an intermittent kill situation, loosing spark. I would also recheck the magneto air gap on both coils and set them to .010”. Adjusting valves is covered in the manual I attached.
Click to expand...
Ok, thanks. I have set magneto gaps to .010". Re: the carb shut-off, I've tried starting fluid directlyinto the intake manifold. No difference. That's what lead me away from fuel issue. It has good compression turning by hand, I had ruled out valve adjustment solely b/c it doesn't even try to start, no backfire etc. (wrongly maybe?).
Now with spark on both plugs and starting fluid sprayed into the intake, shouldn't it at least try to start?
 
Simple answer is sometimes NO. Have you tested for spark with the plugs installed? Second, I see many times you make assumptions, which will at times lead you down a rabbit hole. Every experienced tech will tell you that you must check and double check everything when troubleshooting. I’m now going to get you mad at me when I say this. START OVER AT THE BEGINNING!!!
1. Remove the valve covers and check and reset the valve lash.
2. Get 1 or 2 inline spark testers and check for spark with new plugs installed.
3. Check fuel solenoid.
4. Check of wet plugs after trying to start.
Let us know you findings. Remember we are here to help, but not standing next to you while you are preforming tests means that you must paint the most accurate picture you can so we can give you our best guess as how to proceed.
 
Rivets said:
Simple answer is sometimes NO. Have you tested for spark with the plugs installed? Second, I see many times you make assumptions, which will at times lead you down a rabbit hole. Every experienced tech will tell you that you must check and double check everything when troubleshooting. I’m now going to get you mad at me when I say this. START OVER AT THE BEGINNING!!!
1. Remove the valve covers and check and reset the valve lash.
2. Get 1 or 2 inline spark testers and check for spark with new plugs installed.
3. Check fuel solenoid.
4. Check of wet plugs after trying to start.
Let us know you findings. Remember we are here to help, but not standing next to you while you are preforming tests means that you must paint the most accurate picture you can so we can give you our best guess as how to proceed.
Click to expand...
I understand and I don't get mad at anyone trying to help. I was trying to give you as much info as possible as to what I have done.
I have been using in-line spark testers with plugs installed.
I will re-check everything mentioned.
Thanks again.
 
Try this.
Install NEW spark plugs.
Disconnect the coil kill wires.
Remove air cleaner and spray about a 2 second shot of starting fluid into carb. Don't choke it.
Try to start engine. If engine fires up and runs for a few seconds you have spark on at least one cylinder and valves are close enough to run engine.
If doesn't fire then check for spark and valve lash setting.
This assumes the flywheel key is not sheared.
 
Hammermechanicman said:
Try this.
Install NEW spark plugs.
Disconnect the coil kill wires.
Remove air cleaner and spray about a 2 second shot of starting fluid into carb. Don't choke it.
Try to start engine. If engine fires up and runs for a few seconds you have spark on at least one cylinder and valves are close enough to run engine.
If doesn't fire then check for spark and valve lash setting.
This assumes the flywheel key is not sheared.
Click to expand...
Thanks,
I have verified the key is not sheared. I have tried starting fluid BUT I didn't think to open the choke after setting it to start for the initial test. I have good spark on both plugs. I will start over today.
 
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