Originally Posted by Ah Clem
Great information sir!
I do remember that they were much easier to start with an electric starter, than by hand. There was not much of anything in the way of compression, on the ones I owned, and they lacked a properly tapered collect or keyway at the front of the crankshaft where the propeller backing plate was. No amount of tightening could keep the propeller from coming loose (again, I have a sample of two to work with).
The Series 21 were ringed with the same type ring that K&B was using -- called a Dykes Ring. There was some trick, like carrying STP in an injector, or something else of similar weight to amp up the compression for hand starting. I never owned one, however, I'd bet that the same trick that worked for Red Heads would have helped the Black Head motors to grip a prop.
The thrust washer only had dimples on it that couldn't get a grip on maple, nylon, or other harder composition props, but the thrust washers from K&B's GH 35 and 45, plus late model GH 29s, with the sharp edged teeth, fit the RHs perfectly. I'd like to have such a thrust washer now as a spare to use on the McCoy 40 RH that I still have.