Hi,
I got an old OS 120 Surpass pumped engine from a local swap meet recently, and I noticed a very faint hairline crack between the rear cover to the the rear engine mounting hole. The crack is very faint, appearing more like a surface scratch than a crack.
I am wondering if a crack in 4 stroke engine case is as important as in
2 strokes? The crankcase vent for this engine is routed to the intake manifold of the engine.