Cub Cadet Smoking

[RedMF40]

This just started. Mow for an hour or so and engine starts smoking. If I catch it early I see it starts at the back. Oil level is normal, don’t see any big leaks but it is a smell of oil burning which I know well from other engines. So far I’ve just shut it off and waited for it to cool down. Any ideas what I should be looking at? Thanks in advance. Gerrit

 

[wore out]

This just started. Mow for an hour or so and engine starts smoking. If I catch it early I see it starts at the back. Oil level is normal, don’t see any big leaks but it is a smell of oil burning which I know well from other engines. So far I’ve just shut it off and waited for it to cool down. Any ideas what I should be looking at? Thanks in advance. GerritView attachment 74563

I can't easily tell if it's a B/S or a Kohler from the photo, some of these OHV engines are prone to head gasket oil leaks in the area around the pushrod chamber.

 

[J Hamilton]

Looks like a Kohler engine. It could possibly be the crankcase vent cover leaking

 

[RedMF40]

I can't easily tell if it's a B/S or a Kohler from the photo, some of these OHV engines are prone to head gasket oil leaks in the area around the pushrod chamber.

It’s a Kohler. My feeling is the motor is overheating and maybe some other issue as well. It’s running normally, though. On the one occasion—the first time—it happened, I stopped because a lot of smoke was coming off the engine and it felt a lot hotter than normal. Air-cooled, no temp gauge. Guess I can get out my digital kitchen thermometer.

 

[Pete in MD]

This just started. Mow for an hour or so and engine starts smoking. If I catch it early I see it starts at the back. Oil level is normal, don’t see any big leaks but it is a smell of oil burning which I know well from other engines. So far I’ve just shut it off and waited for it to cool down. Any ideas what I should be looking at? Thanks in advance. GerritView attachment 74563

Have you checked the cooling fins under the engine shroud to make sure they're clean and no mouse nests?

 

[Texasmark]

When is the last time you pulled the cowlings off and blew out the crud that accumulates around the cylinder cooling fins......or happens to include the decomposed body of a rat (BTDT)? Oil leaks happen. Have had them bad on a Kohler 20 hp single cylinder, and on some other tractors where the head bolts worked (vibrated) loose. Had one where I put a drain pipe in to extend the engine drain over the side of the frame and it had vibrated loose.

 

[Fritz Maurer]

Take the air cleaner off and determine whether the draft tube is broken or disconnected from the air cleaner housing.

 

[RedMF40]

Have you checked the cooling fins under the engine shroud to make sure they're clean and no mouse nests?

Not sure how I access that but I do have the complete manual for the tractor. It's horizontal shaft. I'll take a look, thanks.

 

[RedMF40]

Thanks for the replies. I only removed the air cleaner so far but that doesn't give much of a view of what's underneath. I do need a new air cleaner so it's good I looked at it. I'll check the manual and see what I need to do to dig deeper. Gerrit

 

[Rodney51Cub]

It looks like a Kohler command engine. The air cleaner base should have 2 triangular holes in it. You can see some of the cooling fins on the flywheel side through those holes. You can stick a air hose in there and blow some of the stuff out, then blow around the cylinder shrouds.

 

[Mule Meat]

Kohler Courage engines on a Cub Cadet riding mowers were well known to leak oil from the bottom of the valve cover. It was caused by a design flaw that allowed oil to pool in the valve cover and not drain back into the engine block like it should.

The leaks dripped oil onto the exhaust and caused them to smoke once it got hot. At times the leak could be hard to detect.

Once you get the engine cleaned as others have recommended. Check the bottom of the valve cover for oil. It may need to sit overnight after running the mower before it shows up if it's leaking.

 

[Larry986]

You will definitely want to pull all the tin off and clean the crud out. It will be everywhere. Watch the little screws cause they like to break.

 

[Absent Minded Farmer]

The CH series Kohler engines also like to leak from the head gasket. The new gaskets you get are the upgraded ones that are a bit more durable. If you redo the head gaskets, check the cylinders for wear right away. The engine on my Cub Cadet is burning oil on one side & leaking oil from the gasket on the other. Hope to get that ironed out this year.

You'd also benefit from pulling the tin off the engine & giving it a good blowdown or power washing. Those engines seem to leak a bit less when they are not getting so hot. And those engines do like to get HOT!

Mike

 

[Blackhole49]

This just started. Mow for an hour or so and engine starts smoking. If I catch it early I see it starts at the back. Oil level is normal, don’t see any big leaks but it is a smell of oil burning which I know well from other engines. So far I’ve just shut it off and waited for it to cool down. Any ideas what I should be looking at? Thanks in advance. GerritView attachment 74563

You've been given great advise by others about pulling the shrouds and cleaning. It was amazing how plugged up our ZTRs (mostly Kohlers) got in a year at work. Finding oil leaks is easier with the shrouds off also.

 

[RedMF40]

Thanks, all. Finished up my mowing yesterday. No smoke but I didn’t run it very long. I’ll carve out some time to get at the engine and do a thorough cleaning and inspection. Been a relatively trouble-free machine, time to show it some love. Thanks again. Gerrit

 

[T.R.K.]

Judging from the circle in your picture, I would guess the crankcase breather gasket has failed. There was a buliten on that a few years back. I think there was a kit that included a thicker cover plate as well as a gasket. If that is what it is, you should see oil around the breather cover plate once you get the air cleaner base off the engine.

 

[Russ from MN]

Check the air filter. Last year I picked up a free mower that was sitting by the roadside, it smoked badly. The air filter was so clogged that it was sucking oil through the crankcase vent tube. I put a new air filter in it, changed the oil, put a new blade on it, it's one of our best mowers!