Small Engines (Lawn Mowers, etc.): tecumseh hm80 bolens snowblower engine, crankcase breather, head gasket

Question
engine lackes power. compression=120psi.looks like blow by near block-head junction.(oil spatter) could be missing a head bolt in this area. there is a hole in shroud where a bolt could have been,but there seems to be a bolt underneath. hard to see with shroud in place.

Answer
sounds like someone had apart,  didn't do job correct.
you need to replace that bolt in head. i would remove them all, check head gasket,  match up bolt missing and replace head gasket .
also fix that shroud . it could be your crankcase breather should be cleaned out wash it out with a cleaner fluid.