What kind of engine does it have, Kohler, Briggs, etc.?

B&S 19.5 HP

THank you.

Engine numbers? Model Type Code

Yes. If you are familiar with engine valves, pull the valve cover and look for something such as a loose rocker stud, migrating valve guide etc. If not, have someone look at it who is familiar with them.

Here's the link to the engine info:

http://www.tractordata.com/lawn-tractors/000/6/3/638-john-deere-la115-engine.html

I'm not familiar with engine valves, but there's no time like the present to start. How to I expose them, and what should I look for?

Thank you!

Here's a better number: 31P677/0140-B1

OK. I opened it up and had a look. The exhaust valve rocker arm stud was backing out, and the rocker arm was consequently very loose. I think that all I need to do is to clean up the threads and hole, apply locking goop, and re-insert. The one thing that's puzzling me is that there doesn't seem to be a cap on the exhaust valve, and I don't see one flopping around anywhere. I was very careful when I took the valve cover off, and am sure that it didn't fall out then. And when I re-tightened the rocker arm stud, there didn't appear to be enough slop to accommodate the cap. Should the exhaust valve have one?

I looked carefully, and couldn't find it. I took off the push-rod guide plate, and peered down the channel behind it, and still didn't see it. It appears that that channel is designed to not let a part that big get into the sump. Could it be that the engine wasn't built with one in it? In any event, I ordered one for it, along with a new rocker cover gasket. The original appears to have been the silicone adhesive type.

I repeated the above, and DID find it. Thanks for the nudge. Good call Tomplum.

Sweet!

OK, I put it all back together, and adjusted the valves, and it won't start.

I tried both valve settings listed for my engine: .003" intake and .005" exhaust, and .005" intake/.007" exhaust, assuming the intake valve is the upper valve. The adjustments were made with the piston 1/4" lower than (past) TDC.

I pulled the plug and cranked the engine, and the plug fires fine.

I tried starter fluid. No joy. : - (

Help!

A couple of things. Determine TDC of the proper stroke by watching the intake valve. When the valve activates and comes back up, that is the proper stroke. The intake valve is actually the lower valve. if you were to look at the head's insides, you would see that the intake port runs kind of diagonal downward. The exhaust is the top valve. You'll be mowing in the morning....

You hit both nails right on the head. Runnin' like a champ. You da Man.