Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!

stlcardsfan88

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Hello Everyone, Hoping someone could help me on this issue!

I am at wits end with my Toro Recycler mower with a Kohler XT-675 engine on it. Currently this engine will spit oil (with velocity) out the crankcase breather which vents into the air filter box. Usually it puts enough oil in the air filter to fill the carburator and stall the engine. This ends up with either requiring a carb clean or a few week sit for most of it to drain back out and allow to start again. I have verified multiple times that oil level is within specs. For someone to visualize how much force the oil is being pushed with, you can imagine without the air filter on, the oil is propelled out the air box 1-2 feet away from the mower.

One thing I read online is the float in the carb may be stuck open thus causing the engine to flood and the oil to thin out raising the level higher and thus making it come out the breather tube on the crankcase. I have rebuilt the carb and it is still having oil blow out the crankcase breath. One thing to note is the oil is not thin and does not have a strong smell of gas either.

I have rebuilt the breather with a new spring and disc under the recoil starter of the mower with the assumption it was staying open allowing oil past it. This also did not fix it.

Other things I have done to try and remedy this is done a valve job. Both the intake and exhaust where about 0.002" out of spec but are within spec now. Still, none of these remedies have helped.

Next things would be to check if the clearance between the cylinder wall and piston rings is within spec, but I have not had a chance to tear it down that far yet.

Details of the engine are : Spec No PH-XT675-2011 serial number 4210428758

Does anyone have any ideas or known fixes for this issue?

Thanks in advance to everyone who tries to help!!!!
 

bertsmobile1

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Your head gasket is leaking between the cylinder and the push rod tube.
This is often a by-product of a leaking carburettor because if you try & crank it with liquid fuel in the cylinder, the liquid can not compress so it blows out the gasket.
 

stlcardsfan88

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Your head gasket is leaking between the cylinder and the push rod tube.
This is often a by-product of a leaking carburettor because if you try & crank it with liquid fuel in the cylinder, the liquid can not compress so it blows out the gasket.

Thanks Bertsmobile1 for the response. I do not have the time to do a more comprehensives tear down to replace the head gasket on this mower currently. Is it possible to just block the tube leading into the air filter housing from the crankcase breather for now? Will the back pressure caused by clamping that hose cause issues with the engine? Was this a common problem on these mowers? Are there other signs that the carb was leaking liquid fuel into the intake besides the symptoms I have been describing? The reason I ask is I have been checking the spark plug and there are no signs that the mower has been running rich.

Thanks!
 

bertsmobile1

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
No that will not work it will only get worse and blow the seal on the dip stick tube and then the fuel pump if it has one.

If you need to use the mower disconnect the breather tube.
Block off the hole in the filter housing then run some more hose on the breather to a catch bottle which will slowly fill up with oil.

Check the oil, if it smells like fuel then the oil must be changed .
Failure to do this will destroy the engine very quickly.

It is all of 2 to 3 hour job if you have never done one before.
Whip the blower housing off ( 4 bolts )
Undo the tip handle and stand the mower on its back so the cylinder is pointing up.
On some mowers you need a weight on the handles to stop them falling over.
Undo the two bolts holding the carb manifold to the head, leave the carb attached to it and move it out of the way.
Leave the muffler in place undo the 8 or 9 bolts holding the head in a criss cross pattern

Assembly is the reverse.
Dont have to do it in one hit.
1/2 hour after dinner over 3 or 4 nights.
 

stlcardsfan88

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
I had a chance to pull the head on the mower. Please take a look at the pictures. The head gasket seems to be in great condition with no visible damage other than slight separation when removing it. Could the rings really be bad on a three year old engine only used for 4 months out of the year? IMG_1681.jpgIMG_1682.jpgIMG_1683.jpgIMG_1684.jpg
 

stlcardsfan88

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
No that will not work it will only get worse and blow the seal on the dip stick tube and then the fuel pump if it has one.

If you need to use the mower disconnect the breather tube.
Block off the hole in the filter housing then run some more hose on the breather to a catch bottle which will slowly fill up with oil.

Check the oil, if it smells like fuel then the oil must be changed .
Failure to do this will destroy the engine very quickly.

It is all of 2 to 3 hour job if you have never done one before.
Whip the blower housing off ( 4 bolts )
Undo the tip handle and stand the mower on its back so the cylinder is pointing up.
On some mowers you need a weight on the handles to stop them falling over.
Undo the two bolts holding the carb manifold to the head, leave the carb attached to it and move it out of the way.
Leave the muffler in place undo the 8 or 9 bolts holding the head in a criss cross pattern

Assembly is the reverse.
Dont have to do it in one hit.
1/2 hour after dinner over 3 or 4 nights.


Hey Bertsmobile1, Any chance you have additional ideas on what could be causing this oil problem?

Thanks!
 

bertsmobile1

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Well those shots do not show what I was expecting to see.
Just how smokey was that engine when running ?
That is a really badly coked up piston & head.
If it was in my shop the next step would be taking the scotch brite to the piston & head looking for cracks.
I can not see any obvious leakage points,
Also run a steel rule across the head and barrel to check for flatness
 

ILENGINE

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Is the exhaust valve sealing. It just looks like it isn't setting flush on the valve seat in the head.
 

stlcardsfan88

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Well those shots do not show what I was expecting to see.
Just how smokey was that engine when running ?
That is a really badly coked up piston & head.
If it was in my shop the next step would be taking the scotch brite to the piston & head looking for cracks.
I can not see any obvious leakage points,
Also run a steel rule across the head and barrel to check for flatness

I will go tear back into it now. But this mower never burned oil or smoked except when the oil from the crankcase mades it way through the air filter compartment back into the carb. Sometimes you could see white exhaust, but that was always eventually followed by the carb getting fuel of oil and the motor choking itself. I will clean both the head and piston tonight and see what I find.
 

stlcardsfan88

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  • / Kohler XT 675 Spitting Oil Out Crankcase Breather - HELP!
Is the exhaust valve sealing. It just looks like it isn't setting flush on the valve seat in the head.


Hey IlEngine, Thanks for the reply. I will take a look at the seal but when I looked it seemed flush. I will see if I can't get any feeler gauges to judge the gap if any.
 
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