I have a 3 year old 26 horse (kohler) craftsman tractor. It did not smoke until after todays oil change. I refilled it with 64 OZ (two quarts) (as specified) but now after running a while it starts to smoke when the rpms pick up, such as blades bogging down and govener picking up speed or throttling up. Did I pop a valve seal? It can't be rings, because she would smoke all the time. Is there a way to tell what it is? And when to call in the pros? Will it harm the motor further to ru it while she smokes?

I checked the oil and it is at the proper level, and I checked for a pinched breather tube as mentioned. But now I start it up and see she is actually smoking from the breather tube and not the exhaust. I also see smoke in the crank case. Now what could be causing this?
The engine is model CV730S a 25 horse kohler engine

Well, first of all, did you check oil level on the dipstick? At first this sounds like an over filled case. Next I would check the status of your breather hose that it didn't get pinched or plugged in some way.You should be able to find it connected to the air filter canister. Also what type of oil are you using?

Good Luck,
Morrowrj

Most if not all Kohler tractors have an oil filter, sounds as it too much oil was put in, ck the oil level, oil should not be above the line, if so, try this, pull the plugs out, and clean or replace, if that doesn't stop the smoking, that's beyond my expertise.

Also check the oil for the always anoying gas smell. It is not uncommon for the fuel to leak past carb needle and fill crankcase with a fuel oil mix. It is suspect that this is an issue after you filled it with the proper amount of oil. Maybe you did not get it ALL out.

Don

I checked the oil and it is at the proper level, and I checked for a pinched breather tube as mentioned. But now I start it up and see she is actually smoking from the breather tube and not the exhaust. I also see smoke in the crank case. Now what could be causing this?

Sounds like a bad breather to me. What engine is it that your are running, model #? I believe there was a service issue with these at one point but I can't rememeber for sure.




Morrowrj

The breather facilitates crankcase vacume and would only cause smoking if it was functioning improperly. If the machine does not maintain vacum it will push oil into the air filter and burn it in the engine causing exhaust smoke. I hate to sound redundent but it sounds as if it is a fuel oil mix causing crankcase VAPOR. Not much else as I see it will do this.

Don

Can you explain how you saw smoke in the crankcase? Was this in the oil filler tube? Also what color is the smoke ?
Not sure which type you have, but I believe your engine service manual should be available here:Service & Owners Manuals - Service & Support - Kohler Engines
This is the section that I thought relavent to your problem:
A spring steel reed and stop is mounted on each bank of the crankcase, between the lifter bores. When the pistons move downward, air is pushed past the reeds into the cylinder head cavities. On the #2 cylinder, the upper end of the head is completely sealed by the rocker cover, so a low, positive pressure is created in the head cavity. The #1 rocker cover has a hole in it for venting. The bottom nipple of an oil separator canister is fitted into the hole with a grommet. From the top nipple of the canister, a breather hose goes back to the air cleaner base. The air moving into the #1 head cavity is filtered
Through the oil separator and then is drawn into the air intake. The upward travel of the pistons closes the reeds and creates a low vacuum in the lower crankcase. The combination of low pressure above and low vacuum below forces any accumulated oil out of the #2 head area into the crankcase. On the #1 bank you have atmospheric pressure above and vacuum below, again drawing any oil toward the crankcase.

I assumed a blockage in this section, however if you see smoke in the case itself, then I don't see how this could be the reason

I have to say, if this is only occurring at higher rpms and under load, I would lean towards a blown head gasket. These 25hp Kohlers were known for this problem. The blown gasket pressurizes the crankcase and blows oil/smoke out the breather tube. I would like to get a second opinion though, as the OHV isn't as easy to check.

Morrowrj