418 ran great, now dead

[cod 120]

Tractor has been running flawlessly for years. Starts right up with no problem. Today I fired it up to move a large plant, dragged it to it's new spot and shut the 418 off. Came back about 3 hours later, turn the the key and while the engine cranks, it won't start. I first checked the two fuses and they were okay. I then pulled both plugs and they looked fine but I still cleaned them and put them back in. I also tried holding one next to the block while cranking to see if there was a spark but I didn't see one. I can smell gas so I think the fuel pump is okay but the no spark has me puzzled, so suggestions are welcome.

 

Thanks!

[gwest_ca-(File Mod) 11,046]

You should have magneto ignition and no power required for that.

The ignition is simply grounded to shut it off.

 

[BESTDOGEVER 218]

It sounds like the module is gone. You can check the kill wire to make sure it hasn't grounded out, I have lost 2 of them to  bad ignition switches. A spark tester is the best way to check it but you can try spraying carb cleaner into the carb,that will pretty much tell you if there is any spark present. They are available both from Kohler and aftermarket I have been able to find oem ones that I didn't have to trade my favorite grandkids for but that's getting harder and harder to do. If you do have to replace it be sure to check the ignition switch for any short circuit as it only takes a millisecond to kill the module and you are out a couple hundred bucks. You can check for voltage at the kill wire both with the ignition on and off 

[BESTDOGEVER 218]

You can unplug the kill wire from the connector and try starting it making sure it is not grounded if it starts you are looking for a grounded out wire going back to the ignition switch plug

[953 nut 55,285]

 

Could be as simple as the PTO switch not being completely disengaged, give it a little jiggle while the key is in start. 

[Rick3478 428]

Seat switch kills spark on a lot of models.

[c-series don 8,718]

I would purchase a simple spark tester, they are cheap. This will tell you for sure if you have spark. I know this might sound stupid but it’s nice out of gas is it? A gentleman posted here last week going crazy trying to find out why his tractor wouldn’t start after he walked away from it while it was running. He came back and it was not running. Yup turns out it ran out of gas after he walked to his barn! I think it’s happened to the best of us! 

[cod 120]

Thanks Guys!

I'll fool with it and let you know.

[Darb1964 1,043]

I think that has a low oil safety system that will prevent spark if its low.

[cod 120]

So armed with good advice, the manual and wiring diagram, I somehow managed to get it running again. I lucked out in that nothing was shorted out/burned out and what appears to have caused the problem was dirty connections. I took the dash off and connector that runs to the ignition switch and washed that out with electrical cleaner along with the two fuse holders and the connector the goes to the rectifier. All of them were cruddy and then I cleaned all of the grounds that I could find. I also tested the ignition switch, the ignition module and the wires that ran from the rectifier according the Kohler manual and they all passed. Once that was done, I put everything back together, I turned the key and off she went. I did notice that the 25amp fuse might have been getting warm so perhaps unknown to me, resistance was slowly building up in the harness. Hopefully the cleaning solved the problem as I really do like the 418 and the longer I can keep the little bounder running, the better.

 

Thanks again for the advice!

[BESTDOGEVER 218]

Glad to hear you got it resolved without having to replace the module. I agree with you on the 418 being a good little tractor. Keep an eye on the ignition switch both of mine melted the plug and shorted to the ground/magneto wire and goodbye module. Sounds like what you did should head that off for a good while good save.