Tecumseh OHV16 overheating

[Brian Stovall]

I recently stole a Snapper term with a 42" deck. It had not run for a couple of seasons, so I got it for $75! My only concern is that it has a OHV16 Tecumseh engine, but I brought it home, flushed the fuel system & she fired right up. I cut my father-in-law's grass and took her back to the house & cleaned her up & put her away. The next day I went to use her & she wouldn't hit a lick. I had plenty of spark & fuel, but no compression. I pulled the head & discovered the exhaust valve seat had come loose and was holding the valve open, thus no compression. After several hours of research I decided to peen the seat back in. Mission accomplished, she fired right up this evening when I got her back together, however I noticed the muffler pipe was glowing cherry red, so I shut her down for the evening, hoping to do some more research, but the storms have cut my satellite Internet down to almost nothing, so I am hacking this out on my phone. Could it be that the muffler is clogged, or maybe I missed something inside? Anyone have any ideas. I don't usually work on Tecumseh engines, most around here are B&S or Kohler. Would anyone out there by chance have an old dead engine laying around with a good head they might sell?

 

[DaveTN]

With the exhaust pipe glowing red, it's running way too lean! I had one Dynamark 8 HP rider run so hot you could see the shadow of the valves going up and down through the muffler.

 

[Carscw]

Have never had this happen on a mower but on a Chevy 400 it would mean the timing is 180 out or a intake gasket leak.

(( racing is the only sport that you need two balls ))

 

[Brian Stovall]

Thanks for the info. I think that the exhaust valve is not sealing completely, allowing combustion to happen in the exhaust causing the muffler to glow red. I purchased a used head that the seat has never been out of, but in the process of lapping the valves I have discovered that the exhaust valve is still leaking. I have lapped it 3 times now with both coarse and fine grit compound & have a good ring around the perimeter of the valve head. The intake seals fine, it's just the exhaust that I am having issues with. Any ideas? Will this seal itself with carbon? I don't want to put any more labor into this project until I can be relatively sure the thing will run & not burn the entire engine. Thanks for any insight!