RE: OS engines users Club
Here's my list beginning in about 1965.
2 Strokes
H 35 C
S 30 R/C
H 40 P
H 40 R/C times 3
H 40 FSR times 2
H 45 FSR times 2
H 60 FGP times 6
H 60 FSR
H 80 R/C
4 Strokes
FS 52 times 2
FS 61
FS 70
FS 91
FS 120 times 3
FS 120 II Twin
The only dud was the H 40 P in which the unbushed connecting rod ends went egg shaped in about 3 hours running time. This engine was made to compete with the front intake K & B's in the sport pylon racing class, which it did quite sucessfuly, however longevity was not one of it's strong points.
Still using the H 60 FGP's and H 45 FSR's and the 4 strokes, all of which have many hours of running time.