ORIGINAL: w8ye
Looks like it could use a couple idlers on those belts?
Amen! I had one of the original Conley 1.20s, an OHC design. It had fixed idlers on the timing belt; thus no automatic tension adjust when the belt stretched. The belt would jump cogs in a heartbeat if a mechanical transient occurred; say a minimal prop strike on soft turf. It was a real PITA to re-time because it required dismounting the engine to get at the belt/pulleys. Maybe jumping a cog isn't as important on a SC belt, though. (?)
I sold the engine to a German collector.
CR