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Discussion Starter · #1 ·
Hello,
I started smelling some burning rubber this afternoon while mowing and shut things off for a look out in the field. PTO belt is still fine, lost mowing capabilities on the deck, the blades spin by hand with little to no belt tension resistance, and figure the non JD belt (before I learned I should stick with true JD belts) I installed got tangled up or jumped the pulleys in the tall thick grass.

Hopefully not a big deal but I’m more concerned about what I noticed next.

The PTO cover has always been missing on my 110 and only today did I realize the bracket it mounts to has always been missing, too.
The camshaft pin top right of the PTO pulley is protruding from the block about 3/8”. I have never noticed this pin before but it clearly started to work its way out of the block. Nothing about this seems right.
Does this sound like a missing cover or circlip or an impending engine explosion?

Thanks for the help.
 

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The pin should definitely not be working its way out of the engine. They are only a friction fit, so there's no pin or clip holding it. It's driven into the block from the flywheel side of the engine during assembly. So something is obviously wrong here, perhaps the pin has somehow worn itself out and it no longer fits properly? But there shouldn't really be any way that it can wear out.

Are you able to drive the pin back into the block? or is it stuck where it is?
 

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Discussion Starter · #4 ·
I was able to push the pin back into the block with the backside of a screwdriver handle although it’s still protruding about an 1/8”.
I refrained from using a punch/hammer until further investigation.
The pin was spinning when the engine was running, maybe a half turn every second (not continuously but with a regular cadence).

now knowing this sleeve pin is a tapered pressure fit, i’m wondering if the tapered cup in the case got worn out.

If it is a wallowed out case, I don’t imagine this is repairable, no? how bad of an idea would it be to fab a simple keeper tab for the interim? even if it is repairable, sounds like I should start tracking down a replacement K181 for parts and/or rebuild in the near future. I was really hoping to get through this mowing season without a mid summer overhaul.
 

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So, me admittedly being ignorant of small motors basics, what function does the camshaft pin provide? Inquiring minds, you know.......
 

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On these engines, the camshaft pin is about 1/2" diameter and goes all the way through the block, from one side to the other. On these engines, the camshaft is hollow, and spins on this pin. The pin is not supposed to be turning in the block. I will guess that at some time, someone installed the camshaft pin from the wrong side, making it a looser fit.
I would think that somehow you have to stop the pin from turning, as otherwise it will just keep getting looser. It might work to use a center punch on the block to tighten things up a bit, but that could crack it too. I'm not sure what the answer is.
 

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I've got 2 answers, neither which are correct, but will work!
OP states pin was "pushed" into place. I'd get a SMALL hammer, 6-8oz ball peen or even carpenters hammer, and gently persuade the pin back flush with block. If it doesn't seem to want to move, DON'T beat the he!! out of it! After pin is as far in as it will go, my 2 answers:
1. Get Loctite 290 and apply. This is "self-wicking" and will be drawn into any space by means of capillary action.
2. Take tractor to a GOOD welder and have him tack weld the rod to the block. ONE SMALL tack weld with a nickel rod will stop it from turning. Weld can be ground off for true/correct repair.

This should hold for the summer mowing and then plan on a full dismantle to see what's going on inside! Bob
 

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That is so weird, the cam spins on a pin rather than on bearings. Crazy! Is that normal practice on small engine designs?
 

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Discussion Starter · #9 ·
Thank y’all for the responses and info. I’ll check back in with a progress report. I’m thinking the loctite will be a straight forward first test.

in the meantime, if anyone has a rebuildable K181 laying around, get in touch and let’s make a deal.
 

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The way the Kohler block is designed the cam is flush on both ends and fits between the walls of the block. The aluminum bearing plate must be removed in order to pull the pin that the camshaft rotates on.
 

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Discussion Starter · #11 ·
after cleaning up all the caked on oil, it appears someone else already tried center punching the side of the camshaft pin. either that, or they mangled it all while driving it in from the PTO side.
9FE8B3AA-35FE-4E3A-8BE2-2E4AF5C3AE75.jpeg

a small punch and a hammer worked to return the pin flush with the case. however, only after spinning the flywheel by hand did the pin wanted to move as if it was hanging up on something. does this suggest yet another imminent failure potential?
 

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That is so weird, the cam spins on a pin rather than on bearings. Crazy! Is that normal practice on small engine designs?
The Predator 420CC I tore apart with a friend a while ago was similar, it just had two holes in the block and crankcase cover for the cam to fit in.
 

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It looks like it has spun enough in block to have already worn hole. Probably the source of the oil causing caking. It should not spin on block. I suggest having someone tack weld it to block, then turn by hand again to make sure cam will still turn and not stuck on pin. If everything goes good with hand turning, I would then clean area good with brake cleaner and dry thoroughly so you can silicone around pin to help prevent oil leak. You can always have this pin bore in block repaired when engine needs overhaul. A good machinist can drill to bigger size and install a bushing to fit cam pin.
 
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Discussion Starter · #14 ·
Is there any way the camshaft timing could’ve slipped or rotated when the the camshaft pin was protruding from the block?

I picked up some wicking loctite that is holding strong so far, however I can’t for the life of me get the engine to start. It has fuel and spark.

two things I’m noticing.

1. while cranking the starter with the air filter off, file and air mixture is coming out of the carb intake and leaving fuel residue on the front grill.
2. the engine is considerably easier to turn by hand than I remember previously.

with the risk of jumping to conclusions, does this suggest the intake valve is stuck open/not seating? and/or did the old worn original piston rings finally give way?
 

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It's possible, but highly unlikely, that your cam jumped timing... the pin would not be inline with the hole in the block and wouldn't go in.

Remove tappet cover and inspect valve lash... do not adjust simply check. If exhaust is close to spec and intake is wide/much more than spec, probably stuck valve or piece of carbon/debris on seat. Either report findings or pull head and inspect. Bob
 

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Discussion Starter · #16 ·
It's possible, but highly unlikely, that your cam jumped timing... the pin would not be inline with the hole in the block and wouldn't go in.
Bob, thank you for the help. I’ll report my findings when I have the time to take a few things apart. The part that worries me is I was only able to push the camshaft pin flush with the case after rotating the engine by hand. My thinking at the time was enough pressure from the hi lobe keeping the pin from moving. Hopefully that was not a major mistake.
 
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