Craftsman Kohler engine stuck both intake valves in the guides

[Auto Doc's]

Hello folks,

This problem is a first for me to come across. Craftsman/MTD CMXGNAM211704 zero turn with a Kohler PS-KT735-3077 engine.

The customer brought it to me after we had discussed some troubleshooting steps over the phone without resolve.

When it arrived, I check for compression and it had none on either cylinder. I pulled the valve covers to find that both intake pushrods were bent badly, and the intake valves were stuck in the closed position.

The engine is spotless under the top fan shroud/cover and has no debris is the cooling fins.

The engine had a 3-year limited warranty but is expired because the build date is 09/10/2021. It has no hour meter on the machine, but it has been well kept in a garage.

I looked up parts and found the bare heads have updated parts numbers.

Has anyone run into a similar issue on this engine design before?

 

[sgkent]

maybe bad fuel that varnished the stems and they grabbed. I did not believe in that being a possibility but have seen some videos of carbon build up on valves, guides and stems when old fuel is used that the volatiles have escaped from. Even 3 or 4 months can be enough to do it. Then there are people who add products to the fuel to stabilize it, but sometimes those products work and sometimes they turn into gels and make matters worse. This brave new world technology is hammering all of us.

 

[Auto Doc's]

Hello sgkent,

I am going to tear into it depending on how the rain holds out in my area. This has got my curiosity peaked as to what I will find out. The owner has been good about using non-ethanol fuel, but I don't know if any additives mixed in. The fuel tank is practically empty.

When I do get into this, I also need to verify the cam has not broken the compression release mechanism with this damage.

After pricing the parts and reasonable labor to replace the heads, the owner might want to consider a new direct replacement engine