Small Engines (Lawn Mowers, etc.): Oil Leak On Tecumseh Engine, head gasket, head bolts

Question
Hi John. I appreciate any help you can give me. I have a 1983 Troy-Built Rototiller with a 6HP Tecumseh engine on it. The model number is HH60 1C5115H. The serial number is 3054D. I lent the tiller out to a relative, and you guessed it, it came back broke.  I gave it to a friend of the family to get it fixed. He said it had a cracked head and a bent valve.  It looks like he put a used head on it, but it seemed to run good.  Only problem now is, there is oil leaking out of one of the head bolts and it also looks like maybe some oil leaking out of the breather.  I'm disabled (a lot of back operations), but I was so frustrated when I saw this, that I took the head off and cleaned everthing up to try to find out how this oil could be leaking out of a head bolt. Could it be that I need a new head gasket?
I thank you for any help you can give me.
Doug  

Answer
 Hello Doug

 A new Head Gasket is always a good idea anytime the cylinder head is removed. A used head if it is not warped or cracked is good to use.

 As for the oil problem; from what you said this tiller was overheated and that is why the the cylinder head was cracked and the valve bent.  It would also explain why the oil is leaking from the head and the crankcase vent. The oil you see leaking out of the breather is from this vent. This tells me the rings have collapsed or broken due to overheating.

 If you need more help please feel free to let me know.

 Respectfully

 John