Thanks Tahoe, just wonder why the OH150 and OH160 are the same in specs?
OH150 and OH160 probably have different carb or exhaust to give different HP rating.
Or ??? the 15hp OH150 really is a 16hp engine that they rated at 15hp for marketing purposes.
HH80 and HH100 are the same bore/stroke, same displacement, again different carb or exhaust ???
One might be a detuned version of the other as I have found a restrictor plate in between the carb and block on 1 Tecumseh engine I took apart.
OH140 is the same bore/stroke as the HH80-HH100, the higher hp rating comes from overhead valve vs flat head.
I'd like to point out that a Honda or Honda clone, 13hp is a 389cc engine.
OH140 is a 14hp, 388cc engine, same displacement but has 1 more hp than the newer Honda type engine, done 40yrs ago.