Kohler CV23S, smoke, won't start, comp. OK – what’s wrong

[Thanks_a_million]

Hi

I have a CV23S Kohler commander 23V twin on a 46” Cub Cadet. Spec 75604

Yesterday I almost finished mowing my lower back yard, about 1.5 acres, when it suddenly stopped. It may have run out of fuel. I didn’t actually check, as I knew it was low. I put my reserve small can of fuel in, tried a restart and it cranked a bit, but no go. Might have been the slope, fuel not getting through. I got more fuel and put a bit more in. It then started, but blew quite a lot of smoke. It normally puffs a little smoke when it’s been sitting a week or so, but this was a cloud. I stopped the engine, checked the oil level and spark plugs - plugs were slightly oily. I cleaned then, let it cool and tried again.
It started again, but blew quite a lot of smoke. It also made a cracking noise, like something cracked/broke. Shut it down quick. Pushed it to the garage.

Borrowed a compression tester. They tested at 115 and 113psi. Spark plugs look oily.
Tried to start it. No go.

Happened to try to turn it over with left plug out, strange thing it started (and blew smoke). Stopped it. Put left plug back in, but it won’t start.

So that’s where I’m at now.

Any clues would be very helpful, before I start pulling it apart.

Thanks, Mark

[bgsengine]

replace spark plugs?

[StarTech]

Need the engine's spec number too. Several of versions of CV23 that went on the Cubs.

But first have you check the oil level?

[HondaG100]

Starfire has it. Likely a problem with the needle/float letting fuel into the oil.

[Thanks_a_million]

Need the engine's spec number too. Several of versions of CV23 that went on the Cubs.

But first have you check the oil level?

Yes, I should have mentioned that I checked the oil level. It's fine (new oil and filter recently).

(Sorry, I'm not at home when posted this, so don't have spec number at present, will get it later)

Thanks, Mark

Update: Spec number 75604

Update 2: re-measured compression and it is showing 165 and 175 psi

[Thanks_a_million]

Starfire has it. Likely a problem with the needle/float letting fuel into the oil.

How would I check this?

When I checked the oil all looked OK, but I did not do anything in particular to check for fuel in oil. - no smell of fuel when I checked oil.

(Had a problem with my B&S 16hp once, when needle valve went and was letting fuel into cylinder when it sat for a while.)

Thanks, Mark

[Thanks_a_million]

replace spark plugs?

No I haven't replaced the plugs - were new not long ago. Other than oily they look ok. I cleaned them in fuel and put them back in.

Thanks, Mark

[bgsengine]

replace spark plugs?

No I haven't replaced the plugs - were new not long ago. Other than oily they look ok. I cleaned them in fuel and put them back in.

Thanks, Mark

New is not the same thing as Good. Suggest replacing them anyway Its a relatively common issue and your symptoms description is what pointed me in that direction. Spark plugs can fail at any time,and have intermittent issues that cause a whole bunch of weird issues, so replacing plugs with fresh new (or twice, even - have had plugs that were bad right out of the box) is a valid troubleshooting step without more involved technical troubleshooting and experience..

[Thanks_a_million]

New is not the same thing as Good. Suggest replacing them anyway Its a relatively common issue and your symptoms description is what pointed me in that direction. Spark plugs can fail at any time,and have intermittent issues that cause a whole bunch of weird issues, so replacing plugs with fresh new (or twice, even - have had plugs that were bad right out of the box) is a valid troubleshooting step without more involved technical troubleshooting and experience..

Thanks, but main issue is blowing lots of smoke suddenly when it does fire up, though compression seems ok to me at 115 psi. So, yes can go buy some on my way home and replace them, but I really need help with why the smoke and other strange things.

[bgsengine]

what color is the smoke? Black/ dark or blue-grey-whitish color?

If it is black smoke, its getting too much gas, and the float needle or carburetor may be the issue - if it is blue-grey (some call it white) it's burning oil and you may have a bad breather or more likely, a blown head gasket.