Kohler CV-15 sounds awful


Old 09-22-08, 05:13 PM
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 51
Kohler CV-15 sounds awful

Hi, all;

Wheel Horse riding mower, 350 hours
Engine is Kohler
Model CV15S-41550 (Command Vertical-shaft 15HP Electric-Start)
Family: SKH426U1G2RB
Spec No. 41550
Engine size 426 cc
Serial 2812823131

Used on Wheel Horse 265 tractor, for hauling little wagon around 15-acre property, pulling heavy loads of firewood, compost, soil. Works hard. Not used for mowing, ever.

Started it warm out in the field one day, and it made a racketing noise as if the flywheel had a rock in it or something. The noise gradually went away over a minute or so. Checked the flywheel for damage, and there is none. This is a belt drive tractor, so it is not likely to be flywheel damage.

Have run it briefly several times since, under no load but myself, and it sounds like the muffler is coming off, or is loose, but it is not. It is as tight as can be. It gives about 60% power at full acceleration up a gentle hill, and misses slightly even when just sitting at idle.

When starting, occasionally the flywheel only turns part of a revolution, and does not hit the spark cycle unless I use the "rhythm method" -- hit the start key just at the point when the flywheel is recoiling from the previous (failed) start. On the third try or so, it goes all the way around, and starts.

When turning it off, it sounds like the piston is rubbing, kind of a very faint screeching sound, and it backfires half a second after after the engine stops.

On starting again warm, it produces a huge cloud of unburnt blue smoke most of the time.

Any advice? What can I do myself, and what needs to go to the dealer for work?

Thanks for any insights or advice.

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Old 09-22-08, 07:32 PM
Speedwrench's Avatar
Join Date: Apr 2008
Location: Oklahoma
Posts: 1,698
sounds like you have a broken ring, you will need to pull the head and look at the cylinder bore to see if it has any scratches. if so it will require a overhaul.

if you can run a compression check and repost.

life begins when the kids leave home and the dog dies
Old 09-22-08, 07:56 PM
cheese's Avatar
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Join Date: Jul 2001
Location: USA
Posts: 16,818
Check your oil. Is it overfull and does it smell like gas? If so, post back. If not, remove the valve cover and check the rocker arms. Is one or both loose?

Has anything recently been done to the engine (coil replacement, etc...)?
Old 09-23-08, 10:34 PM
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 51
Hi, guys;

Thanks for the advice. I do not have the means to check the compression here at home. I just know that it the tractor has lost a lot of its pull.

I will check the oil and rocker arms tomorrow or Thursday.

Thanks again,

Old 09-25-08, 12:39 PM
Join Date: Sep 2008
Location: pa
Posts: 1
hi i have the same cv15hp kohler eng it run fine for me for about one hour of cutting than the gas filter runs dry it quits I have changed the plug,gas and oil filters dumped out allold gas but it seems to be when i am almost done and go up a hill this happens any ideas

please help
Old 09-25-08, 03:52 PM
Thread Starter
Join Date: Apr 2006
Location: USA
Posts: 51
Follow Up Post

Hi, again;

Pulled the spark plug. It looks exactly like it should, nice grey color, no black deposits, no burned or warped spots. Checked the gap, and it is .030". No gas on it.

Which is as expected, since this engine starts right up almost every time, and runs steadily except for the compression weakness and very slight stumbling occasionally.

Pulled the valve cover, one bolt broke right off. Valves are tight and the oil is in good shape. Does not smell of gas, has good viscosity.

Air filter is in need of changing. Oil filter is due as well, so I will do those two things before I take Betsy to the repair shop. I've heard elsewhere on this forum that a rattling sound on a Kohler engine went away after these two items were refreshed. One can hope, eh?

Thanks again for any advice.

Old 09-27-08, 01:10 AM
cheese's Avatar
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Join Date: Jul 2001
Location: USA
Posts: 16,818
Kohlers have hydraulic valve lifters, and they can occasionally develop a clatter if the oil becomes too thick for the lifters to operate properly. Change the oil and oil/air filters and refill with 10w-30 oil and see if the clatter goes away. I usually use SAE30w oil in all air cooled engines, but kohlers sometimes run quieter with SAE 10w-30.
Old 09-28-08, 06:08 PM
30yearTech's Avatar
Join Date: Oct 2006
Location: Central Texas
Posts: 1,176
I might add to cheese's post, that after the oil is changed you may have to run the engine for awhile before the rattle will go away, if it's due to dirty oil in the lifters.
Old 09-29-08, 07:11 AM
Join Date: Feb 2008
Location: usa
Posts: 755
Kohler has issued four different Service Bulletins that may relate to your noise problem. If you would like copies PM me with an email address and I will send them to you.

SB193 (1-99) New Lubricating Oil & Fuel Recommendations (All Models) OHV engines require multi viscosity oil

SB214 (10-95) Hydraulic Valve Lifters (CH11-CH14, CV11-CV15, CH18-CH25, CV18-CV22) All about lifters

SB231 (4-95) Pre-Fill Oil Filters (K582, M18-M20, MV16-MV20, CH11-CH14,CV11-CV15, CH18-CH25, CV18-CV22) To supply of oil at startup after filter change

SB264 (8-02) Valve/Lifter Noise on Command Engines (CH/CV11-16, CV460-495, CV17-25) Engine changes to prevent noise
Old 05-01-09, 08:27 AM
Join Date: May 2009
Location: South Alabama
Posts: 1
Dredging up an old post here, sorry. But I have the exact engine. Kohler Command CV-15S, 41550.

The other day I'm mowing and instantly it went unbelievably lowd. Scared the pooh out me! I figured the exhaust broke or the muffler blew a hole in it.

Sure enough the "header" broke completely in 2 where it attaches to the muffler.

Here's the question. I've looked on the Kohler website for a new muffler, their website only shows a bracket, couple studs, and a gasket. No muffler. Calling Kholer, they say the muffler was made by Toro. Call Toro, they say I have to request through a dealer. Call the dealer, they've been hunting it down for a couple days now with no success.

This engine is mounted on a New Holland riding mower. The muffler is a "round" muffler, not a "pillow" muffler. The exhaust pipe is pointed forward-left. The only markings on the muffler is "279 NELSON."

Can anyone give me a hint as to where to find a replacement muffler? Or is this a good reason to buy a zero turn?

- JyRO

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