Riding Mower (Kolher engine) problem UPDATED - Changed out Ignition Coil and success!

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stejus

stejus

Minister of Fire
Jul 29, 2008
1,227
Central MA
I'll keep it short and maybe someone can give me some ideas where to look next.

Was running fine and then it started to periodically sputter.
Shut it off, started it and did this serveral times throughout the day successufully.
Tried to start it and it wouldn't catch.
Cleaned air filter and added some starter fluid and it started
Shut it down, and then tried to start and it wouldn't start.
Changed plug with a new plug (not the right plug) but it started.
Shut it down, and tried to start and it tries to start, but it will not turn over.
Sprayed starter fluid and that didn't work either.

Does this sound like a fuel delivery problem? I checked the fuel line and filter, there's fuel in the line.
 
Make and model and how old?
 
Since you got a no start with the starting fluid, it's ignition. The symptoms you describe are classic "dying coil" symptoms. You can disconnect the kill wire from the ignition coil and check for spark to be sure. If you get spark then you have a wiring issue or one of the safety/ignition switches is at fault.
 
My Deere (Kawasaki V2) did exactly the same thing- replaced plug with correct one and added red Sta-bil to the ethanol-treated gasoline. My auto parts guy said this is common with small engines running ethanol-treated gas.
 
Spec's and answers to above

Kohler 14 hp Veritcal Crank (Age - 12 years homeowner use)

Battery is new (one month usage, and it cranks strong)

This gas is fresh but I added stabil to it because I thought I was done for the season a month ago. I've been running the engine with 87 octane with stabil for about a month.

The plug is not the right plug (not gapped right either) it's just a new plug I had on my bench. It did start once with this plug.
 
Had a similar problem with my lawn tractor. It would start and run fine for a little while then die and would not restart. After sitting for 20 minutes it would start run for wawhile then quite. Found that the tiny vent on the gas cap was clogged causing a vacuum in the tank.
 
I just fixed this very problem in the same engine for a friend. Mastermech is right. The coil is most likely the issue. As he said, remove the kill wire and check for spark. New coil runs about 45.00 from amazon/Mowtown.com.
 
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stejus said:
Shut it down, and tried to start and it tries to start, but it will not turn over.
Click to expand...
Explain the "will not turn over" part. If it isn't an electrical issue, the cylinder could be hydro-locked. Pull the plug and dry out the cylinder.

If the engine uses auto-decompression, it could be a valve lash adjustment.
 
LLigetfa said:
stejus said:
Shut it down, and tried to start and it tries to start, but it will not turn over.
Click to expand...
Explain the "will not turn over" part. If it isn't an electrical issue, the cylinder could be hydro-locked. Pull the plug and dry out the cylinder.

If the engine uses auto-decompression, it could be a valve lash adjustment.
Click to expand...

I might have used the wrong words. It cranks, meaning I can hear the piston moving up and down like it would normally do when starting, it's just not starting. I am going to get a new plug and start from there. I'm hoping its the plug because the one in there is not the right plug for the application,
 
I had the same problem with a Kohler engine and I removed the fuel line from the filter and squirted gas in the line from a bottle. It fired right up until the line was empty. This told me it was a fuel issue. I blew out the filter and put seafoam in the tank. Took a couple of tries and now it is running like a champ. Seafoam has saved my butt more than once. Used it in my Quad and Chainsaw too, that ethanol is a real problem.
 
It could be low oil switch if you have one.
As said, if no start on either then it is not getting spark for one reason or another. Coil or low oil switch
 
Problem solved... Thanks for all the responses... I purchased a new proper plug and gapped it. Installed and it fired up right away! I was also lucky enough to find the service manual for this engine so I’ll have that going for me in the future!

Hope you all had a great Christmas and let's look forward to a Happy "Warm" New Year!
 
I thought I had solved the problem but obviously not. This has happened three times in a row now. I put in a fresh plug and gas and this has happened three times now.

Start engine and it runs for about 20 minutes and then I hear a short misfire but it continues to run. Two minutes later, it shuts down. I try to start it and it will not start. I wait a few days or weeks and the same thing. It starts but shuts down about 20 minutes into the run. Is something shorting out here? I don't think its a fuel delivery or carb issue as it runs fine when its running. Any ideas at this point?
 
Sounds like a coil issue.
As it heats up the insulation resitance breaks down and shorts out. Sometimes the right amount of humidty in the air can cause the symptom before starting.
I've also seen corrosion build on the flywheel which will cause poor coil charging.
When it starts to act up when hot, pull the sp boot and install your other plug/grounded and see if sparks(this will save you from pulling a hot plug)
 
BASOD said:
Sounds like a coil issue.
As it heats up the insulation resitance breaks down and shorts out. Sometimes the right amount of humidty in the air can cause the symptom before starting.
I've also seen corrosion build on the flywheel which will cause poor coil charging.
When it starts to act up when hot, pull the sp boot and install your other plug/grounded and see if sparks(this will save you from pulling a hot plug)
Click to expand...

And that's why I love this forum. I would never have thought to do this step. I did pull the plug to see if it was burnt or fouled but didn't think to see if I was still getting a spark. I'll do this next time for sure.

BTW, how difficult is it to swap out an Ignition Module that sits right near the flywheel? Anyone ever do this on a Kokler Command 14HP Vertical Crankshaft?
 
When it shuts down, immediately pull the spark plug and ground it out on the engine. Turn the engine over and see if you have spark or not. If not - your probably looking at coil as said above. If you DO have spark, we have more work to do.
 
Jags said:
When it shuts down, immediately pull the spark plug and ground it out on the engine. Turn the engine over and see if you have spark or not. If not - your probably looking at coil as said above. If you DO have spark, we have more work to do.
Click to expand...

Planning on do this on Friday afternoon after the rain ends. I'm hoping it's the coil as the fuel system seems fine as of know.
 
Jags said:
When it shuts down, immediately pull the spark plug and ground it out on the engine. Turn the engine over and see if you have spark or not. If not - your probably looking at coil as said above. If you DO have spark, we have more work to do.
Click to expand...

Agreed, electrical sounds like the culprit. Fuel system issue that manifests itself after 20 minutes is pretty unlikely, but not impossible.
 
I know you said you checked fuel lines and had fuel, but check fuel lines again as you may have small cracks at fuel tank connection and again at the carb.
I had similar problem with my Kohler same symtpoms as yours, if they are old you may need to replace them anyway..it wouldn't hurt....
just my .02
mark_ms
 
stejus said:
BASOD said:
Sounds like a coil issue.
As it heats up the insulation resitance breaks down and shorts out. Sometimes the right amount of humidty in the air can cause the symptom before starting.
I've also seen corrosion build on the flywheel which will cause poor coil charging.
When it starts to act up when hot, pull the sp boot and install your other plug/grounded and see if sparks(this will save you from pulling a hot plug)
Click to expand...

And that's why I love this forum. I would never have thought to do this step. I did pull the plug to see if it was burnt or fouled but didn't think to see if I was still getting a spark. I'll do this next time for sure.

BTW, how difficult is it to swap out an Ignition Module that sits right near the flywheel? Anyone ever do this on a Kokler Command 14HP Vertical Crankshaft?
Click to expand...

It is very easy. Simply take the cover off the engine and you will see the coil attached with two screws. Remove them, remove and replace the coil. Make sure the arrow is going the same way as the flywheel turns.
 
This may not apply, but I had a similar issue last year. Crank, but no start. Fuel, not a problem, but no spark.
Checked the plug and it was wet. Hmmm.
Pulled the motor housing to find a couple dead mice in a nest in a recess on the engine. The problem turned out to be that they had chewed the coil wires, and it would start with difficulty, run a bit, then not start. Must have been shorting.
Fixed it, and it runs like a champ now, although I had another mice issue and found 2 more that got caught in the flywheel a bit. Not a happy ending for the mice. Slightly crispy too, which is why I kept smelling mice burgers.
 
Before you go spending money on modules Kohlers are famous for gummed valve guides that can exhibit your exact symptom's. After the engine gets hot the valves will start sticking and of course the engine will run rough, maybe shutdown. Later when it cools it may fire right up like nothing happened or maybe not. Do a health check on the motor my pulling the plug, put air pressure on the cylinder with it on TDC and see when the leaks are going. A sticking most like exhaust valve will blow air out the muffler.
 
Stejus,

Have you checked out the ignition system? It's relatively easy to do especially if you have a neon inline spark tester like this one.



And they're cheap too.

http://compare.ebay.com/like/230672359854?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

Like Jags mentioned, gotta know what's going on with the ignition system before we go any further.

With one of these testers you just plug it in, run it till the engine starts to act up and then you can see instantly whether or not the spark pattern has changed.
 
There should also be a capacitor which is meant to absorb the extra voltage from the coil firiing
they absorb moisture also and fail
would be cheaper than the coil and if it doesnt fix it
you should replace it with the coil anyway
 
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