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Discussion Starter #1
Pulled out my Simplicity Sunstar for the first time this season that has a Kohler Command CH20 in it, prior to winter storage the whole thing was seafoamed, the carb was cleaned, and the oil was changed along with a new oil filter.

I ran it for about 3 hours, cutting my fields and lawn, fired right up and worked perfectly, then i hit a snafu. I bottomed out in a drainage ditch and got stuck. RPMs dropped super low and i started puffing white smoke. Immediately shut off the engine, got myself out of the situation and fired her back up. Hard hard start, 20 seconds of cranking before she fired up very slowly, but once going, ran smooth and I mowed for another 2 hours with no issue and good power.

Pulled her in front of the garage to do a post mow-cleaning, and upon turning over again to pull into the garage, no start, just slow crank. Engine voltages are good, fuel pump is working, etc.

It was getting dark at that point, so i figured maybe it was a heat issue, and let her sit overnight. Went out again this morning and cranked it over. Once again, super hard start, but did eventually turn over.

White smoke, running rough for maybe 5 seconds, then knocking, bad knocking....

what did i do to my engine :( Im not too familiar with the kohlers, but i cant imagine i threw a rod or something like that (oil level is fine, etc).

Suggestions on what i can check (push rods, valves, something stuck?)

tl;dr

bogged out my engine
white smoke, extremely hard starts
started up once after a hard start, ran a further 2 hours without issue
wouldnt start second time, when it finally did the next more, rough engine, white smoke, and knocking

I shut off immediately on hearing the knocking to prevent further damage. Help!
 

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First I would check for a sheared key on the flywheel which would alter the timing making the unit run poorly and potentially causing early or late ignition either of which would abuse the piston, rod, crank, etc.
 

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Id pull out the plugs, its not uncommon for a small engine to knock if oil or fuel has made its way into the intake/cylinders, if the plugs are dry, id recheck the oil level, check the air filter for being oil logged or plugged up...

Then id try to crank it with the plugs in, but the wires off...and if it cranks normally, not slow, or uneven, no odd sounds, put the wires on and see what happens.

Grey smoke, means oil...and knowing the Command Twins had a history of blowing head gaskets, its something to consider.
 

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Discussion Starter #4
Id pull out the plugs, its not uncommon for a small engine to knock if oil or fuel has made its way into the intake/cylinders, if the plugs are dry, id recheck the oil level, check the air filter for being oil logged or plugged up...

Then id try to crank it with the plugs in, but the wires off...and if it cranks normally, not slow, or uneven, no odd sounds, put the wires on and see what happens.

Grey smoke, means oil...and knowing the Command Twins had a history of blowing head gaskets, its something to consider.
Will do, that was in the plans anyway for next daylight, to isolate which side its on at least by pulling and checking plugs, individually, etc. Air filter was clear of oil, already checked that. Its worth a second check though, I was mowing an exceptionally dusty field that could have clogged it up good.

The crank is really ugly right now, its slow and louder than usual. Doesnt sound right at all.
 

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Thats just all kinds of not good...I dunno, it sounds bad. Commands usually spin over really easy, with no effort.
 

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Discussion Starter #6
Ill take a recording of the sound when i try to crank it up next. Its just extended (like the sound you'd get when you have a low battery, even though battery amps are just fine). RRRRRWWWWW RRRRRRRWWWWW RRRRRWWWWW rather the RR RR RR RR RR
 

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Maybe you jarred some stuff loose in the battery. I had one that cranked fine, moved the mower around to give it a bath, and it wouldn't crank the second time, almost as if the safety switches were cutting power to the solenoid. I found it was the battery after chasing stuff for a couple hours.
Is the knock connecting rod bearing or lifter tapping? Were you tilted so that it may have starved the bearings of oil? Minor bearing transfer can become major over time, leading to a journal with bearing material wiping out the rest of the bearing.
If you turn it over manually, taking time in the compression stroke, does it have a 'hard' spot or rotate with about the same force needed? Operating the valves takes effort, but a bearing on its way out will need more force to rotate the crankshaft. More or less, eliminate the starter/batter/solenoid for sure before condemning the engine.
The description of the smoke would seem to say you got oil into the combustion chamber, but it would have burned off rather quickly. Two hours running without problem point to a non-damaged engine. Failure to crank later made me say look at the starter. Manual rotation if possible will tell a tale.
tom
 

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Discussion Starter #8
Maybe you jarred some stuff loose in the battery. I had one that cranked fine, moved the mower around to give it a bath, and it wouldn't crank the second time, almost as if the safety switches were cutting power to the solenoid. I found it was the battery after chasing stuff for a couple hours.
Is the knock connecting rod bearing or lifter tapping? Were you tilted so that it may have starved the bearings of oil? Minor bearing transfer can become major over time, leading to a journal with bearing material wiping out the rest of the bearing.
If you turn it over manually, taking time in the compression stroke, does it have a 'hard' spot o
The description of the smoke would seem to say you got oil into the combustion chamber, but it would have burned off rather quickly. Two hours running without problem point to a non-damaged engine. Failure to crank later made me say look at the starter. Manual rotation if possible will tell a tale.r rotate with about the same force needed? Operating the valves takes effort, but a bearing on its way out will need more force to rotate the crankshaft. More or less, eliminate the starter/batter/solenoid for sure before condemning the engine.
tom

Were you tilted so that it may have starved the bearings of oil?

Yes, 20-25% tilt or so.

Is the knock connecting rod bearing or lifter tapping?

Im afraid im not experienced enough to tell the difference, my very first through was connecting rod and I shut it off immediately before i threw the rod and completely screwed myself, but i could be incorrect. If i make a recording of the sound would that be helpful?

More or less, eliminate the starter/batter/solenoid for sure before condemning the engine.

10-4
 

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Discussion Starter #9
If the ch20 didnt have hydraulic lifters, i would think that i might have messed up my valve timings somehow, or maybe have a stuck valve someplace. I could still have the stuck valve i guess
 

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Discussion Starter #11
Ok, update

1) Crank sound with spark plugs in, WRRRRR RRRRWWW RWWWWW slow, about one sound per every 1.5 seconds. I recorded a video but for some reason it got deleted
2) Crank sound with spark plugs out, RRRRRRRRRR, constant crank, fairly normal sounding
3) Inspection of spark plugs: long story short, theyre a complete mess

Right plug:

Left plug:


Put a cloth in each spark plug socket and tried to crank, no oil came out on the cloth.

4) Popped the air filter, some oil where it shouldnt be, but not soak through or that big of a mess

Filter:

Carb plate (larger puddle):


5) Popped off the OHV covers.... well, theres a very obvious problem

Right rockers and general area looked fine


Left rocker set.... well, theres my knocking most likely




Ok, so in summary, I essentially have two problems:

A) oil somehow got everywhere it shouldnt, gummed up my plugs, probably contaminated the carb pretty decently. That explains the hard starting to a degree
B) Somehow a rocker popped off of the valve (push rod is still seated) and thats my chatter/knocking. This was the very last thing it did, i havent run the engine for more than 15 seconds total like this, its very noisy and clearly something was wrong, so maybe no permanent damage?

So I guess what im asking now, is whats my recovery from this?
 

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Discussion Starter #12
Hmm, upon further reading, might i have a collapsed hydraulic lifter? Id rather not have to take the head off if i dont have to. This engine has NOT been through the service bulletin update that replaced the hollow push rods with solid ones for kohler engine to the best of my knowledge
 

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The engine does not have a method to index the stanchions to the head. Line everything up and torque the stanchion bolts to 100 INCH pounds. Then, with the plugs removed, rotate the engine by hand for two revolutions to make sure the lifters are not too far extended. Replace the air filter, put the plugs back in, and go. If you still have a blow-by problem, it could be a head gasket(s), common problem on that engine.
 

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Discussion Starter #14
The engine does not have a method to index the stanchions to the head. Line everything up and torque the stanchion bolts to 100 INCH pounds. Then, with the plugs removed, rotate the engine by hand for two revolutions to make sure the lifters are not too far extended. Replace the air filter, put the plugs back in, and go. If you still have a blow-by problem, it could be a head gasket(s), common problem on that engine.
Im going to go ahead and show my ignorance here, and I sincerely appreciate your patience in advance

Question 1: The stanchion bolts (cant find the term looking at the kohler manual) are the bolts holding the rockers on?

Question 2: How do i know if the valves are too far extended after rotating it twice?


Secondly, im a bit stuck on how to manually rotate the engine, I cant get to the drive shaft to the best of my knowledge and id have to dismount the engine to do it via the flywheel :/

I've been doing a bunch of reading and am trying to understand how the valves, rockers, push rods, and hydraulic lifters are related, and if they have to be "Tuned" to be in sync. That is why i didnt immediately just loosen the bolt on the rocker and reseat it and call it a day, i was concerned i might mess up a tuning tolerance.

Mind treating the problem like im a 5 year old? I have to start learning somewhere, and this is currently a bit beyond my skills.

I do have a torque wrench and can torque the stanchion bolts to 100 inch pounds (once i figure out which ones are the stanchion bolts), but without access to the drive shaft im still trying to grasp the rest of it
 

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Just loosen the rocker that is out of alignment, re align rocker to valve and tighten bolt. Crank engine over with plugs out for a second and watch that nothing pops out of alignment. Re install new plugs and try starting it.


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Discussion Starter #16
Just loosen the rocker that is out of alignment, re align to valve and tighten bolt. Crank engine over with plugs out for a second and watch that nothing pops out of alignment. Re install new plugs and try starting it.


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10-4. That i can do. Will do at next daylight and report back
 

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Also I'd change your oil and fill with 10w30. Your oil doesn't look the best.


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Discussion Starter #18 (Edited)
Also I'd change your oil and fill with 10w30. Your oil doesn't look the best.


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which is so strange to me, this mower has been out ONCE this season, for about 3 hours and at the end of last season prior to winter storage i changed the oil completely (10w30 of course)

I noticed the same thing ,the oil looks ugly, but its quite literally brand new.

edit: that said... ill change it, it cant hurt
 

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The stanchion bolts are the ones holding the rocker arms. The purpose of rotating the engine by hand is to assure that there is no valve to piston interference. If you can't easily turn the engine, let it sit for an hour before trying to start it. That will allow an extended lifter to collapse to its correct dimension.
 

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Discussion Starter #20
The stanchion bolts are the ones holding the rocker arms. The purpose of rotating the engine by hand is to assure that there is no valve to piston interference. If you can't easily turn the engine, let it sit for an hour before trying to start it. That will allow an extended lifter to collapse to its correct dimension.
perfect, thanks for the clarification and your patience.
 
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