Repairs LT1046 23hp CV23S Kohler- when pour fuel donw carby it starts -clouds of blue smoke

[what?]

Hi
I have a Cub Cadet LT1046 with a 23hp CV23S Kohler commander V-twin (Spec # 75604)
A couple of weeks ago I almost finished mowing my lower back yard, about 1.5 acres, when it suddenly stopped. After some trying it started again, but blew clouds of light blue smoke.
It also made a cracking noise, like something cracked/broke. Shut it down quick.

What I found/did so far:
Spark plugs look oily. Cleaned the plugs, I get a blue spark when I test them. It fires fine with fuel down the carby, so I assume spark is ok, at least short term.
Checked fuel line, pump & solenoid fuel to carby OK (actually now I think about it when removed solenoid, fuel runs out, so fuel getting through). Thoroughly cleaned carby - jets, float and all look ok.
Borrowed a compression tester and it tested at 165 and 175 psi - manual states 165 psi.
I did a bit of a DIY leakdown test using compressor. The only noticeable air is when I put my finger over the breather - after a short while I release it and some pressure has built up.
I put fuel down the carby again and it fires up for a few seconds, then stops. Blows a lot of blue smoke.
Someone suggested head gasket. Heads off - old head gaskets, reed valves look OK.
I tried with new gaskets first on 1, then on 2. It does not run for more than a few seconds with the new gaskets. Still blows smoke.
Took cylinder 2 head off again as it is now my hunch that it is the problem - has some oil in it.

So that's where I'm at. Need to find:
1. Cause of the crack sound, like metal snapping
2. Why won't start (without fuel down carby)
3. Clouds of smoke when I do start it

Any clues would be very helpful.
Thanks, Mark

 

[Deerlane]

Does you motor oil smell of fuel, is it over full?

 

[what?]

Does you motor oil smell of fuel, is it over full?

Thanks for responding.
I should have mentioned that. No, oil is normal and at correct level.
The mower has been well maintained. Had service about 6 hrs ago - oil, filters.

The bores look smooth, unmarked. The tops of pitons & heads have an even coating of carbon - as far as I can see nothing unusual.

 

[tybilly]

check your breather assembly for dirt,could be a valve seal also

 

[what?]

check your breather assembly for dirt,could be a valve seal also

Air filter, breather assembly are all off at present. Still smoking.

Could be valve seal. Don't have valve spring compressor, so haven't checked these. Would valve seals go suddenly? Would they make a crack noise?

BTW Engine did not overheat as far as I can tell.

 

[tybilly]

sorry I should've been more specific,crankcase breather assembly,should be on top of your engine near the throttle control mechanism,another thing could be a worn out oil ring,...as my mentor once said..if its made by man its going to fail..lol

 

[what?]

No expert here.
Is it the breather assembly that runs from tappet cover to air filter. air filter.is off, thus breather is off.

What is most likely? Valve seal or ring - with oil in cylinder & even coating of carbon on piston tops and heads.

Mark

 

[Deerlane]

A engine will run with out a oil ring.
You say it wont start and making a noise.
You are saying it wont start or run. But yet it smokes when put a little fuel down the carb and it tries to start.
Is it oil smoke or a rich fuel smoke?
There is a compression release on the cam making the noise in the case. If you have heads off crank engine over to see if noise in still there.
With heads on you can see the rockers dump compression on #2 cly if working proper. The rocker will move around .008, very little.
It all most sounds like two things going on.

 

[Fish]

Sounds like you need to tear it down and know what you are looking at.....

 

[what?]

Many thanks for your help, much appreciated Deerlane.

Is it oil smoke or a rich fuel smoke?

When I start it with fuel in the carby it could be I suppose. I'll take better note of the color when I do it next (head is off at present)

There is a compression release on the cam making the noise in the case. If you have heads off crank engine over to see if noise in still there.

No haven't heard that noise since the first time I tried to restart it in the garden (it's now in garage)
When I turn it over there is no noise. So that could be it. If it is, is it anything to worry about?

It all most sounds like two things going on.

Yes, it may well be. Something to do with 1. carby/manifold and 2. smoking.

I'm wondering if there is a small crack in the inlet manifold or something like that.

Are they prone to anything like this?