bgsengine wrote:KE4AVB wrote:First it has hydraulic lifters so there is no adjustment for the valves as they are self adjusting.
Leak down is at TDC Compression but it is possible to test the whole stroke if you disable the valve train.
Maybe someone with more experience with Kohler engines will chime in.
Well if I was sure of piston position (measuring through plug hole, not guesswork based on flywheel position due to possible sheared flywheel key) and had those leakdown results, I'd be pulling head (or using a boroscope) to inspect cylinder bore for possible upper cylinder damage that gets sealed once the piston is down far enough to reach undamaged area... which would make me wonder if maybe something didnt go through carb (like a throttle plate screw) and get sucked into the engine...
I think that's it. So here's the latest. I pulled the valve / rocker cover. Not sure what I was looking for but as a newbie, but I'm a lot more comfortable doing a leak down when I can see the valves. I also pulled out the dipstick which I don't think I did initially. (I know...rookie)
So at TDC, I was putting about 50lb in and it was holding about 28. From my experience, that's a problem. And sure enough, it was blowing pretty good out of the crank / oil tube . No other sounds from anywhere else, or if there were, I couldn't hear it over all noise coming out of the oil tube. This flywheel has a really nice hole bored out of the side, probably for balancing but it with a socket extension, it gave me a really nice anchor to manipulate the piston a little bit to check it at different points.
At TDC with all sorts of hissing coming out of the oil tube, I dropped the piston about a 1/2 inch and the pressure in the cylinder went way up. So it sounds like the top end of the cylinder is the problem.
A couple of notes: The clearance seemed very tight on the exhaust valve. Not knowing much about the hydraulic system, I'm guessing that's normal.
Secondly, and I was puzzled by this: At about 50lb in and 28ish in the cylinder, I decided to push it up to about 60 and the pressure in the cylinder jumped way up, comparatively speaking. To about 50. Almost like the more pressure I put in, the more it held as a ratio. like something was plugging it up. This is the opposite of what I'm used to, with a good engine anyway. Usually, the differential gets larger the higher the pressure goes. So that got me thinking that maybe my gauge was screwed up.
One last point: Since I was using a lever to hold the flywheel, I'm able to feel the pressure. Usually, I have to hold on pretty tight. But the flywheel held on its own, even at the higher pressure. I read that as so much was getting past that it wouldn't even push the piston down. But if I brought the piston down about 1/2 inch past TDC, I had to hold on pretty tight to keep it from flying away on me.
I hope this is useful info and not just a bunch of jibberish.
Thanks
Lefty