Kohler Command 25hp burning oil

[Bleach]

I got more info about the head that I found for under $100. The seller informed me that it was a good head that had been cleaned and the valves and seats were resurfaced. I saw similar carbon staining around the exhaust valve guide on the top of the head. I think I'll just bite the bullet and buy a new head, get new valves and seals. I'm sure I can reuse the valve springs and retainers.

 

[Bleach]

I researched the Husky and it seems to be a little bit light in construction, i.e. light gauge steel, etc. I have areas of rough terrain and I also have a habit of getting very close to stumps, trees, posts and walls. I think I would end up breaking things fairly easily. That's why I decided to bite the bullet and tear into my old machine and give it another chance.

 

[reynoldston]

Just curious, why are you changing the head for oil burning? Worn intake valve stems and guides because that will be the cause of oil consumption. Just how loose are they? The intake wear limit is 0.2809 and the exhaust wear limit is 0.2819. Myself I would check this before investing in new heads.

 

[Bleach]

I can get side to side play with the valves inserted in the guides. I have no way to measure the guides ID but the valves were still within spec but the exhaust valve stem did have visible wear. I did find a machine shop that might be able to rework the old head. If not. I'll probably end up buying a new head.
The problem with these heads are that the guides are not replaceable and have limits on knurling them and then you have to buy valves with oversized stems.

 

[cpurvis]

I can get side to side play with the valves inserted in the guides. I have no way to measure the guides ID but the valves were still within spec but the exhaust valve stem did have visible wear. I did find a machine shop that might be able to rework the old head. If not. I'll probably end up buying a new head.
The problem with these heads are that the guides are not replaceable and have limits on knurling them and then you have to buy valves with oversized stems.

I would be surprised if Kohler didn't make oversize valve guide bushings.

I just did this on a very old 3 hp Briggs engine. The bushings are very cheap and it cost $25 to get them installed by a machine shop. The bushings have the correct ID and the head (or block in my case) is bored or reamed to the correct diameter for a light press fit.

 

[Bleach]

I got the head back yesterday and got it all back together today. It all started fine and idled good for a few minutes but when I increased the rpm's it all of the sudden went wide open throttle and I couldn't get it slow down. I had to choke it to slow it down. I checked the governor linkage and I have it set correctly. The carb throttle keeps opening up if I don't hold the linkage. If I take the small spring off the throttle link and lever it will idle normally but will surge if I increase the rpms. I've tried different holes on the governor lever and it goes WOT every time if I keep the spring attached to the throttle link and lever. For whatever reason the spring keeps it from closing. I'm thinking something might have happened to the governor.
In the meantime my grass keeps growing.

 

[Bleach]

I was reading around the site and came across a thread where some mentioned a clock spring on the carb on a different engine. This could solve my throttle problem but I didn't see any clock spring on my carb. I need to try to find one that would fit. I'm sure one would have enough tension to keep the throttle from opening up on its own.

 

[Bleach]

It runs fine now and doesn't seem to burn oil like before but something in the transmission may have quit.

 

[Harob1]

I have a 1997 Craftsman 50" riding mower with a Kohler Command CV25S 25 hp and it's burning oil bad enough to foul one of the plugs in less than an hour of mowing. It has just under 600 hours on the clock. Compression seems really good with just over 180 psi on the affected side and a little over 200 psi on the good side when warmed up. It's burning oil on the side with the breather on the valve cover. The breather doesn't seem to be plugged. I've read here somewhere that the reed valve could be a culprit but I only have side that burns oil. I had to replace a the valve stem seals on one of the heads before at around 100 hours but I don't remember which side. It seemed to have fouled a little differently that time.
I would really appreciate some help to point me in the right direction this time around.
Thanks in advance.

Bleach, I just acquired a 25 hp Kohler from my neighbor. He said it was smoking bad + leaking oil from the oil pan. Upon tear down, I sure didn't see any evidence of broken rings, in fact rings looked real good as well as the cylinders. I sure see it was burning oil as the number 2 combustion chamber was heavily fouled with carbon. So I would suspect breather issues and or worn valve seals. I'm in the process of rebuilding this engine and both my neighbor and I will have a spare. I too have a 25hp Kohler and run the crap out of my Craftsman in the summer. Mine smokes a bit on start up, and is 17 years old but is a good runner overall. The neighbors engine had some issues, where the crank gear had chewed into the oil pan thrust surface. I'm in the process of machining down the thrust surface .125 and then add a .125 washer and just a little bigger around to spread out thrust. The crank gear which has the thrust bearing surface is ( in my opinion) small?? Kohler says this is not an issue. Will update this overhaul when I'm finished.

 

[Sam335150]

I've seen this problem several times on the 25hp Kohler Command Pro. The way I solved the oil burning problem is I replaced the piston rings with a new ring set that included an improved type 2 piece oil control ring. The stock 3 piece oil ring loses tension and the rails (the very thing upper & lower oil rings) stick to the expander. Therefore, the stock oil control rings become ineffective and you burn lots of oil. The ring set with the improved 2 piece oil rings is available on eBay & other sites - it replaces oem p/n 2410814S. You'll see the 2 piece oil ring design used on many high end engines that need the ring set to last a long time. They are used in Cummins, Detroit Diesel & Caterpillar diesels. They are more expensive to manufacture than the 3 piece design & the last a lot longer and don't lose tension. I've used the 2 piece oil rings in 4 of our Kohlers and oil consumption is virtually nil.