K341 PTO goes BOOM!
 

Just my luck....change oil, air filter, hyd fluid, filter, rear axle seals, rebuild steering box, de-rust gas tank, rebuild carb and take her out for a spin.....
and BANG BANG etc!

Shut it down quick, but it sounded pretty bad.

This will be my first time in a Kohler, so probably will have some questions.

Well, at first glance, it doesn't seem the piston is connected to the crank!

I hate it when that happens. Take lots of pictures.

That sucks! Did it have the balance gears in it? Take your time, have a machine shop bore it
And do it right, do it once!

Just finished a k-241. As stated by others, Bore the block and grind the crank. Follow the directions in the manual and it's not bad at all. Mine is running great. Had an oil leak at first. Used non detergent oil for 1st hour, then drained and put sae 30 wt HD and no more leak NONE. Go ahead and put new points, plug and breaker rod in also. I didn't at first but did after the first day. I had zero experience with a kohler or any other small engine. Just a little with the older
V-8 chevrolets.

Wrong! At second glance, I should have realized I was looking at a VALVE in the spark plug hole, NOT the piston!:bash2:

Looks like something is missing from the PTO, and maybe this is the problem?

Pull the spark plug and see if you can turn it over by hand.

That's the first thing I did. It turned easily and I could hear blowby, which didn't make sense if the piston wasn't moving, but I wasn't looking at the piston! I was looking at the exhaust valve!

It appears to be missing a spring, washer and nut off the front of the PTO brake assy, and the screw that goes thru the spring was getting jammed between the brake clutch plates causing the brake to bang against the actuator arm.....at least that's what I hope was happening!

Put the SG back on and hook up what it needs to run and give it a test to see if it runs. I think you may have over reacted and started to take it apart when your problem is the PTO. They can make ugly sounds when they fall apart.