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Kohler Knock Anyone?


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#1 AllisKidD21 OFFLINE  

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Posted March 22, 2016 - 03:32 PM

Hi everyone, I thought I would post a topic about the infamous "Kohler Knock". I have a couple of old Kohler K series engines (K160 and K321)and they're both great little engines. But I can't help noticing the incessant knocking sound that comes from the K321. I know that the K321 and K341 engines were known for this and I have come up with the theory that it is simply the cam lobes or tappets making the noise as they are solid metal not plastic. It obviously isn't anything that will affect the engine negatively, but I would love to hear the opinions of some of the old Kohler experts.
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#2 olds45512 OFFLINE  

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Posted March 22, 2016 - 03:49 PM

It might be infamous as you say but it shouldn't do it, if the engine has balance gears they could be going bad and when they do they will put a nice hole in the side of the block. It could also be a lose or worn connecting rod or if the piston is lose in the bore it will also do it, I have a k301 apart right now that made a pretty good knocking sound and it turn out to be the piston having a 1/16" of movement in the bore. Could also be spark knock from not being timed properly or from a weak spark.

Edited by olds45512, March 22, 2016 - 03:51 PM.

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#3 BigFlash OFFLINE  

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Posted March 22, 2016 - 03:56 PM

I'm not most experienced, but the explanation i like the most is cam end play, The cam to walking back and forth on it's shaft and make the knocking noise. When i rebuilt mine, it had one shim in from factory, and it took three to get it within spec.


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#4 EricFromPa ONLINE  

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Posted March 22, 2016 - 04:09 PM

Big thing on an old Kohler is piston slap.This will happen way before the connecting rod starts knocking.Once the rings get worn down the top edge of the piston and the sharp top edge on the rings makes contact with the cylinder bore and wears it away very fast.

 

Resulting in a cylinder bore that is egg shaped.

 

Once a kohler starts knocking you can bet on it needing bored out.

 

I've rebuilt quite a few and rarely will you find 1 that's knocking that just needs a connecting rod.


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#5 Username OFFLINE  

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Posted March 22, 2016 - 04:09 PM

You can quiet it down sometimes by adjusting the points.



#6 HANKG OFFLINE  

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Posted March 22, 2016 - 05:10 PM

Knock  Knock,  who's there ?  Rod ,  Rod who?  you'll  see


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#7 mtoney OFFLINE  

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Posted March 22, 2016 - 05:39 PM

I have personaly seen a professionaly overhauled 16hp Kohler still knock at mid to upper RPM's.  What most rebuilders forget is those little cam shaft shims.  The end play has to be measured with a dial indicator to see what the run out is. If the runout is excessive, the cam will slap back and forth creating a "rod knock" like sound.   While piston slap can cause some noise, as can points being to far out of time creating spark knock.  The more common "Kohler Knock" is the cam shaft slapping back and forth.   Ranks up there with guys that are clueless that Onan's need thier valve lash checked every 200 hours or so to keep the engine in balance.  Mike 


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#8 AllisKidD21 OFFLINE  

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Posted March 22, 2016 - 09:06 PM

Ah yes, the dreaded piston slap. I wondered about that being a possibility but I've examined the cylinder wall and it appears to be perfectly round and there isn't a noticeable gap from piston to the cylinder. But I suppose anything is possible, unfortunately. Has anyone ever had a Kohler throw a connecting rod? I don't think the rod is causing the knock in mine as it also appears mint. Thanks to all those who took the time to post on my topic!
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#9 KennyP ONLINE  

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Posted March 23, 2016 - 04:59 AM

Ah yes, the dreaded piston slap. I wondered about that being a possibility but I've examined the cylinder wall and it appears to be perfectly round and there isn't a noticeable gap from piston to the cylinder. But I suppose anything is possible, unfortunately. Has anyone ever had a Kohler throw a connecting rod? I don't think the rod is causing the knock in mine as it also appears mint. Thanks to all those who took the time to post on my topic!

The rod in my K341 let go. It's in many pieces now! May need a crank too!



#10 pidjones OFFLINE  

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Posted March 23, 2016 - 10:39 AM

I'm fairly certain that the knock in my 341 (in a JD 216) is a loose bearing seat. When I replaced the piston, rod, and governor back in the early '90s I knew that the big crank ball bearing (I think it was the PTO end, but I've slept a few times since then) slipped into the plate way to easily. Wish I had use seating compound, but it still runs fine, just noisy.



#11 pidjones OFFLINE  

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Posted March 23, 2016 - 10:43 AM

I'm not most experienced, but the explanation i like the most is cam end play, The cam to walking back and forth on it's shaft and make the knocking noise. When i rebuilt mine, it had one shim in from factory, and it took three to get it within spec.

Did this make it quiet?



#12 AllisKidD21 OFFLINE  

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Posted March 23, 2016 - 01:51 PM

The rod in my K341 let go. It's in many pieces now! May need a crank too!

Aw, that's very unfortunate. Luckily I don't think the rod in mine is bad, if so it would've blown by now.



#13 AllisKidD21 OFFLINE  

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Posted March 23, 2016 - 01:57 PM

I have personaly seen a professionaly overhauled 16hp Kohler still knock at mid to upper RPM's.  What most rebuilders forget is those little cam shaft shims.  The end play has to be measured with a dial indicator to see what the run out is. If the runout is excessive, the cam will slap back and forth creating a "rod knock" like sound.   While piston slap can cause some noise, as can points being to far out of time creating spark knock.  The more common "Kohler Knock" is the cam shaft slapping back and forth.   Ranks up there with guys that are clueless that Onan's need thier valve lash checked every 200 hours or so to keep the engine in balance.  Mike 

Yeah that makes sense, although mine has never been rebuilt. When I replaced the oil pan seal, I was pretty sure that that was the first time the oil pan had ever been off, haha! Maybe I'll play around with the breaker points a bit sometime.



#14 BigFlash OFFLINE  

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Posted March 23, 2016 - 06:00 PM

Did this make it quiet?

It is quieter than before, But the cylinder was bored .010 over  with a new piston, rod, and rings. So all the possible sources of noise were removed at once.



#15 Bassethound OFFLINE  

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Posted April 01, 2016 - 08:10 PM

I'm not an expert. I have my first and only garden tractor(but I love it) and am slowly learning by reading these posts. I have a k341 on my deere 316. Long story short, any knocking I have had over the two years tinkering with her was a fuel issue. As soon as fuel is restricted it will knock. It was a bad knock too. Now she's back to leaking and burning oil but no more knock.
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