The engine doesn't hydraulically locks up, what happens is just that the spark plug gets wet and I guess that prevent it from making the spark. After removing and cleaning the spark plug, the engine usually starts with not much problem.

The difficult part is to know how much to prime the engine without having this problem. How to close the carb. air intake and turn the prop without help from another person?. I had a Zenoah mounted on an UltraStick and I had absolutely no problems with it, I just turned on the choke on the carb. turn the prop and when it wanted to start, I just put the choke in the normal position and it would start very, very easily. This is not being the case with this US engine.

Is there a way to install a choke on the carb similar to the ones used on Zenoahs?

Thanks.