Let's talk Small Engines. 24..16..12 horses

[Petejoe]

Never got into rebuilding any of the small engines on lawnmowers and never owned a cycle. Typically always sold them or owned a junk one that pretty much was a use and throw away type.
Yesterday, the 15 yr old, 12 horse, tecumseh in my rider started backfiring pretty badly. Cleaned the filter and plug, adjusted the carb and ran it for a few minutes more.

My legs were getting hotter than hell! Stopped, open the hood and watched flames coming out of the exhaust about 9 inches in length.
My guesss would be a stuck exhaust valve.
Haven't check the compression yet. What compression can I expect from a tired old 15 yr engine?
You guys have anything more for me to look into.
Sound like its about time for another 1000.00 throwaway?
At 15yrs.. I think I got my money out of this old Craftsman. I've run the shit of it with no problems at all all these years.

[JOECOOL]

My 110 John Deere with a Kohler is a 1979. I swear when it wears out I'll get rid of it.I mowed my 1 acre patch for years and also mow other folks stuff for car money . Be carefull on the compression check,this Kohler has an eccentric on the cam so that at cranking RPM it holds the exhaust valve open a little to help the starter . Mine has almost 0 compression on initial cranking.Your Tecumseh may be the same.

[cornfieldrodder]

My 11 horse Briggs cranked something like 60psi. Its a 72 model, in a 15 year old crafstman chassis(Free!!!!!)It replaced the junk Techumpseh. You could have some carbon stuck on the exhaust valve.I've seen them crack, too. weird stuff happens to small engines. I figure it is due to or inappropriate materials when the bean counters win at the decision table. Those old engines are pretty cheap to go through.