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Need Some Input From The Mechanics About A M18 Kohler


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#1 victor3ranger OFFLINE  

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Posted July 12, 2014 - 07:13 PM

I have a Lawn Boy GT18H that has a Kohler M18 vert engine. Some days I can go out and it will start right up and run great until I have run it for a hour or so then it will just die and it won't start again.

Other times I can go out and it won't start at all. I am getting fuel but no spark.

 

I have already bought a new coil setup for this motor but could this problem be caused from something else?

The seat safety switch has been bypassed already at the plug under the seat.

I don't know my way around these motors yet so any thoughts or help would be appreciated.

 

 



#2 superaben OFFLINE  

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Posted July 12, 2014 - 07:44 PM

The M18 is solid state, so it either works or it doesn't.  It will not work intermittently and run well while it is working. 

 

The sure way to know that is the next time it doesn't start, disconnect the kill wire from the engine that grounds it out when the key is off, and see if it fires right up.

 

I suspect a safety switch or a key switch.  Some makes can have a two part safety switch that (if one side fails) allows you to crank the engine but will not allow it to fire. 

 

I had a similar problem on a Simplicity Sunstar.  It would start sometimes, then cut off.  I found out that a factory jumper connector that blocked off the rear PTO switch (not needed on that Sunstar since it was not equipped with rear PTO) was loose and sometimes it would connect, allowing the engine to fire, sometimes it would not.  It all depended how hard you jarred the tractor getting up and down!

 

Ben W.


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#3 victor3ranger OFFLINE  

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Posted July 12, 2014 - 09:00 PM

Is there a easy way to bypass all this stuff and just run a on/off toggle and push button starter?? If so I would like to know.

I don't mow with this GT, I use it for its 3pt on the back.

I am all ears on how to get this thing going again.



#4 victor3ranger OFFLINE  

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Posted July 12, 2014 - 09:03 PM

Is there a easy way to bypass all this stuff and just run a on/off toggle and push button starter?? If so I would like to know.

I don't mow with this GT, I use it for its 3pt on the back.

I am all ears on how to get this thing going again.

I forgot to add this, when I got the GT it had a push button kill switch on it.



#5 trowel OFFLINE  

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Posted July 12, 2014 - 09:17 PM

Vic,

I am with Ben on this, all the safety switch can be jumped to keep the connections, make sure the connections are good and covered tightly so this does not pop up again, the only wires you would really need is one off the battery to the keyswitch or push button then to the starter solinoid.

 

There should be a black wire from the ignition coil for shut off, that to a toggle switch or push button then to the dash or tractor frame for a good ground.

 

Should be two wires or one, i forget, for the alternator, white and green i think but look in the manual to be sure, that comes from the rectifier under the flywheel showd to the battery for charging or to the amp meter on the dash then the battery.



#6 victor3ranger OFFLINE  

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Posted July 12, 2014 - 11:04 PM

Ok, so tomorrow I will see if that push button kill switch is hooked up to a black wire.

 

I pulled up a wire diagram of the M18 it shows a white wire coming off the ignition module going to a oil sentry switch and to the "M" terminal of the keyswitch they are calling a ground-to-kill lead.

 

And a red and blue going to the solenoid.

It also shows a "AC" on both outer terminal of the regulator/rectifier with a "B" terminal coming from the middle of the regulator (violet) that goes to the "R" terminal of the key switch.


Edited by victor3ranger, July 12, 2014 - 11:47 PM.


#7 HowardsMF155 OFFLINE  

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Posted July 13, 2014 - 07:29 AM

I ran into a problem with similar symptoms on a Kohler-engined Gravely tractor.  It turned out to be the plug connecting to the key switch had overheated and corroded, causing intermittant electrical problems.  I replaced the switch and redid the wiring and it has run great for several years.  

 

By the way, I think it is fine to TEMPORARILY bypass safety switches in an attempt to track down a problem.  However, I MUST advise you to return all safety switches to the manufacturer's original configuration once you finish the trouble shooting process.


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#8 alleyyooper OFFLINE  

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Posted July 13, 2014 - 08:19 AM

I have a M18 Kohler engine in my 25 year old Simplicity. It has had the fuel pump replace once about when it was 18 years old. Second issue when it was about 19 was intermittent start intermittent quitting when the engine got well warmed up. changing the ignition module cured that. A starter at age 20 and at age 24 the ignition module again. That ignition Module doesn't just quit all the time many times it just drives you nuts till you finally believe the reason you have no spark, and then do is the module is off and on PUKING. You have to about strip all the sheet metal off to change it.

I have found when some safety switch is bad the engine just will not crank acts like a totally dead battery.

 

:D   Al  



#9 victor3ranger OFFLINE  

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Posted July 13, 2014 - 01:29 PM

Al, you described what I am experiencing with mine.

I wanted to kick the crap out of it today, lifted the hood, had wiring diagram in hand, tried to trace wire, jiggled some here, some there, made sure the connections under the hood were secure. Touched the key and vrooom!  I was like :tapping_fingers:

 

What the heck let it start this time? :wallbanging:


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#10 victor3ranger OFFLINE  

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Posted July 13, 2014 - 01:33 PM

trowel, I checked the push button kill switch and it appears to be wired with the white wire coming from the coil.

 

 

 

I HATE electrical problems!!!!!!!!!!!!!!! :mad2:


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#11 superaben OFFLINE  

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Posted July 13, 2014 - 08:51 PM

Al, you described what I am experiencing with mine.

I wanted to kick the crap out of it today, lifted the hood, had wiring diagram in hand, tried to trace wire, jiggled some here, some there, made sure the connections under the hood were secure. Touched the key and vrooom!  I was like :tapping_fingers:

 

What the heck let it start this time? :wallbanging:

 

Sounds like a bad connection somewhere!

 

Those are fun to find.

 

Check for anything loose, or any wires that looked pinched or rubbed.

 

Ben W.



#12 DougT ONLINE  

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Posted July 13, 2014 - 09:28 PM

Work the problem backwards. If you suspect a bad connection, wiggle the wires while it is running and see if you can make it quit. I'm with Al on this one. Coils and modules can definitely fail intermittent. It's just hard to part with the money without checking everything else first.



#13 alleyyooper OFFLINE  

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Posted July 14, 2014 - 04:36 AM

A good multia meter, continuity tester is as handy as a 9/16 socket when dealing with electric on old tractors cars and trucks.

 

:D   Al 



#14 victor3ranger OFFLINE  

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Posted July 14, 2014 - 07:04 PM

A good multia meter, continuity tester is as handy as a 9/16 socket when dealing with electric on old tractors cars and trucks.

 

:D   Al 

And out of those 3 things I only have the 9/16 socket :(






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