Kohler K181 hard starting

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Oct 4, 2009
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Location
Litchfield, Ohio
Ive got a wheel horse tractor with a Kohler K181 that I'm having trouble with. The tractor is probably late 70s vintage with 12 volt coil ignition system. The thing has been hard to start for years now. Even warm you have to mess with the choke to get it to fire and it just doesn't start well. Once its running though it runs pretty good. So about this time last year I decided I would take the carb off and clean it and rebuild it. Let it soak in chem tool for a couple weeks and blew it out with carb cleaner. It didn't look that bad from the start but I figured maybe something was gummed up. New needle and seat, new bowl gasket and put it back together. Could not get it started after putting the carb back on. Today I put new points and condenser on it and set the points to start to open when the s mark on the flywheel lines up with the timing mark. Finally got it running after sitting for a year but it still doesnt want to start even warm without choking it and cranking like crazy. Even with a shot of ether its hard to start. It has strong spark too and the spark plug is in good shape. Starting to wonder if it maybe a compression issue? Was reading that these maybe have a compression release on them? I'm not really sure at this point. I think I will check the compression with my compression tester but what kind of numbers should I be looking for?
 
Have you tried draining the tank and starting with fresh gas? Sounds odd but my push mower last year randomly started running rough and I couldn't figure it out. The carb was a little dirty. come to find out the gallon of gas I pumped at the Conoco was bad.
 
From what I understand, there is a fuel pump on your K181. Being that old, its diaphram probably has stiffened up due to age and not delivering fuel as it should. It is also indicated as a lean condition since you are having to choke a warm engine to aid in starting. Probably wouldn't hurt to also check valve clearances.

 
I have one of these. The carburetor is almost always the issue. When you rebuilt did you go through with a fine wire or something similar and clean the needle valves and jets?
 
He said it's hard to start with ether too.. Sounds like we can eliminate fuel and carb for now.


Check the flywheel key - perhaps it's partially or completely sheared? Also check the valves/compression and let us know what you find.
 
Ether not helping would make me think it's a bit low on compression. I'd do a compression test. Does it smoke at all? I just rebuilt the K241 in my Gravely Commercial 10A. It would smoke a little bit, but compression was getting low. Runs fantastic now.
 
Yep as others have said, sounds like a compression problem. Yes they do have a compression relief, so will not have good compression numbers like a car. I personally never used a gauge on small engines, as most do have a relief. I just put a finger or thumb over the hole tight, and if the compression blew my finger off, it was good to start and run ok.
 
From what I understand, there is a fuel pump on your K181. Being that old, its diaphram probably has stiffened up due to age and not delivering fuel as it should. It is also indicated as a lean condition since you are having to choke a warm engine to aid in starting. Probably wouldn't hurt to also check valve clearances.

The fuel pump has been changed once since we got it but its been 8 years or more since. Wouldn't be surprised if it needs it again. At the time we didn't know you could rebuild them so we just got a new one. Think I kept the old one though. Would be nice to rebuild it and stick it back on. The one thats on it is all plastic so I don't know if it can be rebuilt. Going to also get the gaskets for the side cover so I can pull it and check valve clearances.
I have one of these. The carburetor is almost always the issue. When you rebuilt did you go through with a fine wire or something similar and clean the needle valves and jets?
I thought I had it cleaned out pretty good but its hard to say. Really thinking about buying one of the cheap ones off of ebay to try.

Yep as others have said, sounds like a compression problem. Yes they do have a compression relief, so will not have good compression numbers like a car. I personally never used a gauge on small engines, as most do have a relief. I just put a finger or thumb over the hole tight, and if the compression blew my finger off, it was good to start and run ok.
Was doing some reading and apparently you can spin the engine over backwards to deactivate the compression release and get a reading. Going to give that a try next nice day we get.
 
Verify the valve lash and do a valve job regardless just because of age.

I do not recommend what I am about to say unless you are very skilled with engines.

There is a metal tab on the exhaust lobe of the camshaft on these K181 engines, kohler calls it the ACR (automatic compression release). You can use a dial indicator to check valve lift to verify it is in spec. If there is TOO MUCH lift you can position the engine on this part of the tab and tap the exhaust valve a little and reduce the lift as you will simply be bending the tab, but you must do this very careful and continue to check with the dial indicator until you get it within spec. If you go too far you cannot undo it without an entire engine disassembly.

It should lift only approx .005" when it runs over the tab. If it lifts too much it will dump too much compression and make it start very hard.

One other thought, the K181 and M8 are the only engines that when the connecting rod starts to knock, the cap bolt can rub on the camshaft and break it. However when this happens, the crack or break can be asymetrical and still kind of mate up to the gear enough to keep the engine somewhat in time. If this is the case it will start hard. You can check this be removing the pan and inspecting the gear where it mates up to the lobes.
 
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