Kohler CH18S Spec #62513 Simplicity Sovereign

snowman(MI)

snowman(MI)

Forum Newbie
Spent the better part of a day replacing the coils in this CH18s engine. I had suspected that the coils had went bad and purchased some OEM coils to swap out. Earlier the lawn tractor would run for a time and then just out of the blue, die. No sputter or anything , just flat out lights out dead. Try to start again, and nothing. I might hear a slight click but nothing. Wait a minute or two and bingo the started engages and we are off and running for another 3-5 minutes. So I change the coils and I still have the same symptoms only now it runs for a couple of minutes, dies, wait the minute or two and fires up again. Any ideas as to what might be taking ignition that I have to wait the minute or two before the key allows the starter to engage?
 
Tried to start the engine this morning, turned and come up tight. Pulled the plugs, shot gasoline out of one cylinder. Do I head in the direction of the fuel solenoid valve? Makes me think that this cause the engine to stop out of the blue? Searching for ideas.
 
I would start with needle valve. While you have the bowl off, check on the solenoid too, but the needle valve is the main suspect. Change the oil once you fix the problem too.
 
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Looking back at the first post, check fuel flow to carb. You may have crud in the tank, migrating into the carb, and sticking the needle valve open.
 
You can try taking some paste type toothpaste and lapping the seat with the toothpaste and a Q-Tip. Do you have a pressure tester to test to see if that fixed the problem.
 
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I would try losing the fuel cap to see if the vent is stopped up creating a vacuum in the fuel tank.
 
Well, you have determined the coils are not the problem....

From your description, I recommend you wiggle the connector lightly at the carburetor fuel solenoid. They tend to spread the female pins and lose contact after year of vibration and use.

The pins can be tightened slightly using a couple of stick pins and wedge them down the outside edge of each female pin to close them up slightly.

After that, reconnect it and use a small harness nylon cable tie to secure the harness to the solenoid body to keep the wire from flopping around and vibrating too much.

The next suspect would be the main fuse holder has become corroded and not making proper contact with the push-in fuse blades.

Lastly, the ignition switch is failing due to worn contactor pins inside the switch.
 
Saga continues, ended up replacing the fuel solenoid, change the gas infused oil in the crankcase, added manual fuel shutoff and new oil filter. Started it up, run for 3-4 minutes and again quit (lights out). Waited 30 to 50 seconds, starts up and runs for about a minute and light out quits again. Loosed the fuel cap such that it had plenty of venting and again quit. Can't check spark right away because there isn't any sort of signal/sound from turning the key to start until after the 30-50 second wait. Thinking I down to replacing the key switch or the electrical/heat sink device on the side of the fan shroud (don't know what this is). Problem is repeatable
 
If you are talking about the heat sink? That has three wires connected to it that would be the voltage regulator.
 
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