I have a SCAG Turf Tiger with a Kohler CH25S motor Spec number 68579. The mower was running fine and stopped as if it ran out of gas. The motor will turn over but will not start. I have pulled both spark plugs and neither show any indication of spark when grounded but when holding with my fingers I am getting a frequent jolt. I have tried starting fluid in case it was a fuel pump but nothing.
the first thing that I must tell you is DO NOT use STARTING FLUID on these engines, you can ruin the engine by washing off the il on the piston and cylinder and scoring the piston and cylinder.
Ok, not that that is done......
If you can feel spark but it does NOT knock you on your BUTT every time it sparks, then you are NOT getting enough spark. You must have a really good spark...enough to see on the spark plug when it is grounded to the engine. And even many times when you DO see spark in the plug, it still isn't enough. A good spark tester should be used. Just because it feels like it has spark does not mean it has enough to fire a saprk plug UNDER COMPRESSION.
Now we move on to something else. You should test the compression on both cylinders. You should have at least 130lbs sor more on both cylinders and they should test no more than 10 lbs different from one cylinder to the other.
YOu actually may have low compression that could be caused by valves or even a broken piston connecting rod.
If you have spark , fuel and compressionm, the engine shuld run.
One more thing that happens is that the uel solenoid may have stopped working. This is the small cylinder that is attached to the carbuetor that shuts off the gas when you turn the ignition key off. It this goes bad, it will shut off the gas.....but since you didn't get it to run with the starting fluid, It probably is nto the problem here, but it is a possibility.
Here is the COMPLETE Mechanics Service manual for your engine.http://www.kohlerengines.com/onlinecatalog/pdf/sm_24_690_06.pdf
I hope this helps.
"Please leave a GOOD rating for me as that is the only way I get paid for my time. If you cannot give me one of the highest ratings, then please do not rate me AT ALL until we discuss this answer further and you are happy with my answer".
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The mower was in perfect running condition and has been well maintained. No smoking and started good up till now. I do not have a spark tester but did not see any visible spark when grounding either plug. I do have a compression tester but would expect it to be good. The engine quit while mowing and did not make any unusual noise when it stopped and does not make any unusual should when you try to start it. It just sounded like it ran out of fuel or someone shut off the ignition
Yes, I understand, but to find out what really happens we are going to have to do some testing.
We need to start with the spark since that is what you first suspected. and you didn;t see spark on the plugs.
No spark on either plug
You also might have a seat switch or other safety switch that might have gone bad and is not letting it spark.
Then if you do find out that you do have spark, then we have to check other things....such as the compression.
You only have a few things that will make an engine not run.
If you have spark at the right time.....fuel......and compression....then the engine must run.
One of these three things must be missing.
So we have to eleiminate them one at a time.
I can bypass the seat switch and run a compression check tomorrow.
If you put gas in the carburetor or used starting fluid and it will not fire, then the fuel sytem may be ok.
OK, that is fine.
I do not know when I will be back online tomorrow, but if you leave me a message, I will get back to you as soon as I can.
You can leave messages for me even after you give me a good rating .
You also should read the service manual I sent you for more information.
I am not in too much of a hurry. It will be tomorrow evening before doing the checks and the part store will be closed for the fourth.
just let me know if you need more help, but you really should read the manual. They ahve a good section on troubleshooting.
Already gone through the manual
Remember you are rating me on my knowlege and my attemot to help, not on whether I fix your unit or not, but I will be happy to continue to hep you as much as I cann.
Well we'll see what you come up with later, just let me know if I can help further.
Compression is good (150), bypassed seat, same result. It is either start replacing electronic parts or take it to someone that has the equipment to test. I have never let anyone work on my stuff before but believe this one is going to the shop.
Well, if the seat switch is not it, then the ignition col may be bad.
To check the coil, just take the engine cover off and find the coil. Remove the small wire from the coil. Then test the spark and see if you have spark. If you have spark, then you know that the coil is good and the problem is still in the wiring and safety switch syste. If NO spark, then you will know tha the coil is bad.
Mower has gone to the shop. There are two relays and two sets of coils. If I had gotten your email on how to test the coils before sending it I may have been more satisfied. I have a good knowledge of engines and how they work and have overhauled similar ones. I felt the answers you were giving were only basic information.
With me not being able to see the unit and test it myself, the only thing I can do to start with is give basic information.
We most likely would have been able to contact each other several times do go more indepth. Remember, this is a chat room...even if I am not online all the time and we must work together.
Also, sometimes the best answer I can give is that it needs to go to a shop. There are many times that the problem may not be able to be fixed at home."Please leave a GOOD rating for me as that is the only way I get paid for my time. If you cannot give me one of the highest ratings, then please do not rate me AT ALL until we discuss this answer further and you are happy with my answer".
I Own a Lawn Mower Sales and service business (37years). Have 2-cycle and 4-cycle certification.
I checked your good rating although your service was a waste of my time. Will not use you or your company again. Please quit sending me emails
thanks for the rating. I am sorry that you felt that this was a waste of time. My goal is to provide good suggestions for you. following my advice should have helped.