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Kohler K321 Surging: Ready for Shotgun!


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#1 superaben OFFLINE  

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Posted March 28, 2015 - 10:11 PM

For once, instead of being the guy answering engine questions, I get to come to my good friends and neighbors on here with the hope that you all collectively can save a Kohler K321 from getting a good load of buckshot in the gizzard.

 

I think we all have read the upteen gazillion Kohler engine surging issue threads all across the internet.  However, this little K321 has a different issue. 

 

The engine is running a Cub Cadet 149.  It starts immediately, no matter what.  It will chug along so slow you can nearly count each time it fires, and it will run wide open and lug down the thickest grass without sweating.

 

However, if the engine is sitting still with nothing to do, it will surge at full throttle.  No little surge.  It will stroke from idle to WOT back and forth. 

 

So I start down my typical trail.  First, we know the carburetor is adjusted right, and it is clean as a whistle... brand new clean since it just came out of a box!  We know we have the right main adjusting needle. 

 

As we all know, most surging issues on a Kohler are ignition related.  I had already replaced the points, but we scrubbed them with a file just to be sure no manufacturing grease was clogging them up.  New condenser.  New coil.  New spark plug and spark plug wire.  The points are gapped .020. 

 

That leads me back to the governor.  I have a new governor spring on it.  The governor is adjusted correctly on its shaft, and the sensitivity adjustments don't seem to do much good.  I worried that the governor gear was spun on the shaft, but since I see how well this engine lugs down and pulls under a heavy load, and responds very well, I don't see how that can be. Usually a gear issue will result in surging or overreving all the time. 

 

So now we are back to fuel.  My guess is that the engine is running too rich.  However, screwing the needle around doesn't do diddly squat, beyond literally blowing the tail off the muffler during one nice bang! 

 

I wish I had a dollar for all the K321's I've rebuilt, repaired, or sold.  But this one has done me in.  We've been through two tanks of gas together but now that I need a muffler so my hearing will improve does not improve my love affair.

 

So, before the trusty Winchester comes out and gives this engine a final coup, does anyone have any last words? 

 

Ben W. 


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#2 lyall OFFLINE  

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Posted March 28, 2015 - 10:42 PM

sound like a bad governor gear and/or  governor weights


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#3 boyscout862 OFFLINE  

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Posted March 28, 2015 - 11:10 PM

I was going to say the govenor weights too. They may be sticking alittle. A small vacuum leak can be the culprit too. Either of those problems can increase with the rpms. Before taking it all apart, try running it with the governor disconneted to see how it runs. It may give a few clues. Good Luck, Rick


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#4 MH81 ONLINE  

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Posted March 28, 2015 - 11:20 PM

Any response with a can of carb cleaner and hosing stuff down? I had a lme with an unseen crack that did some crazy crap.
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#5 HANKG ONLINE  

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Posted March 28, 2015 - 11:23 PM

Since the carb just came out of the box, try one that is not brand new .


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#6 EricFromPa OFFLINE  

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Posted March 28, 2015 - 11:25 PM

Guessing it has a Kohler/carter carb on it and not one of those junk Walbro carbs.Pull your main needle out and see if the holes are clogged up.Then attempt to blow through it.

 

The carb on my 129 was acting funky and I took the carb apart and found a Bug stuck in the bottom hole that feeds air to the main jet.It was surging pretty darn bad just because a small bug got into it.Funny thing is that it's always had the air cleaner on it so I have no idea how it got in there.

 

 

If it's surging at full speed then it's running extremely lean.Either clogged up or float set to shallow.

 

Might want to try setting the points to around .018.Some like them set tighter depending on Cam wear.I've had to set a couple old kohler points by ear.Some like them set tight some like them set loose.


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#7 EricFromPa OFFLINE  

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Posted March 28, 2015 - 11:28 PM

Walbro carbs on Kohlers don't work very well.If you manage to get one to run out OK it will not idle down worth a darn.


Edited by EricFromPa, March 28, 2015 - 11:28 PM.


#8 propane1 ONLINE  

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Posted March 29, 2015 - 04:42 AM

Vacuum leak , condenser not grounded. Noel

#9 JDBrian OFFLINE  

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Posted March 29, 2015 - 05:35 AM

It sounds like you are covering all the bases. On the ignition side I would carefully check all the wiring in the ignition circuit for a bad connection. As mentioned above, the connection from the engine chassis to the battery- terminal is vital to proper operation and often gets taken for granted. Even a relatively small amount of resistance somewhere in the points/coil circuit will cause a reduction in HV at the plug. If you have a weak battery / charging system that can also lower spark plug HV as battery voltage and coil current are lower with lower battery voltages. None of this stuff may be the issue but at this point it must be something unusual or you would have sorted it out by now. Good luck. 


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#10 Cat385B ONLINE  

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Posted March 29, 2015 - 05:48 AM

Has this been sitting around for a while? I'm afraid it's gotten to know you, and just dislikes you.

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#11 KennyP ONLINE  

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Posted March 29, 2015 - 05:54 AM

sound like a bad governor gear and/or  governor weights

 

 

I was going to say the govenor weights too. They may be sticking alittle. A small vacuum leak can be the culprit too. Either of those problems can increase with the rpms. Before taking it all apart, try running it with the governor disconneted to see how it runs. It may give a few clues. Good Luck, Rick

I'm thinking governor gear/weights also if everything else checks okay! May have to open it up and take a good look inside!


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#12 petrj6 ONLINE  

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Posted March 29, 2015 - 06:41 AM

:nothingtoadd: :ditto:  I agree with most of the others, unhook the governor and run it a bit see what happens.  fi you have the same issue then you know it is in the carb or ignition.  narrow it down a bit.  I had a briggs that did the same thing and drove me nuts for most of one summer, after about the 5th time I cleaned the carb and points and overall got really irritated with it I reassembled and the problem was gone !! no Idea what I did but it worked.   


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#13 Kyocum OFFLINE  

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Posted March 29, 2015 - 06:44 AM

supraben look into the choke end of the carb and see what the stamped # is. They could very well have sent you the wrong size carb. You should see a # 30 in the top of the choke bore as that is what size carb the 321 and 341's use. Maybe you got a 26 that is used on the 301's. They are identical in appearance. I would static time that as well. .020 is usually just a ballpark setting. Just a thought. Kelly


Edited by Kyocum, March 29, 2015 - 06:46 AM.

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#14 superaben OFFLINE  

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Posted March 29, 2015 - 06:50 AM

I really appreciate everyone's input.  Except for Cat's.   I figured someone here might see the stupid thing I missed after trying everything I know for about three hours.  I was probably working on it so long that I missed something. 

 

Guessing it has a Kohler/carter carb on it and not one of those junk Walbro carbs.Pull your main needle out and see if the holes are clogged up.Then attempt to blow through it.

 

Might want to try setting the points to around .018.Some like them set tighter depending on Cam wear.I've had to set a couple old kohler points by ear.Some like them set tight some like them set loose.

 

It is a Carter.  I wouldn't have a Walbro fixed jet if I was paid to do it!  The original carburetor had most of the threaded holes stripped out on it.  However, the engine surged with that old Carter, too.  I'm halfway ruling out fuel. 

 

I will try tightening the point gap. I know for a fact that it does matter to a Kohler where the gap is. 

 

I'm thinking governor gear/weights also if everything else checks okay! May have to open it up and take a good look inside!

 

That was my thought, too, but the last one where I found that governor weights were a problem the engine would surge all the time.  This one clears up under load and handles perfectly...under load only.  That seems to tell me the issue is elsewhere.  If I can't find anything else I will have to try that, though. 

 

It sounds like you are covering all the bases. On the ignition side I would carefully check all the wiring in the ignition circuit for a bad connection.

 

Excellent points, Brian.  I will double check my grounds.  Someone else mentioned condenser ground. 

 

Ben W.


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#15 superaben OFFLINE  

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Posted March 29, 2015 - 06:51 AM

Has this been sitting around for a while? I'm afraid it's gotten to know you, and just dislikes you.

 

You know that shotgun I am threatening to turn on the Kohler?  Keep it in mind.

 

Ben W.


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