Dave,

A 16/10 is about 20% higher prop load. What prop size do you suggest?

Thanks for the information about modifying the carburetor. I usually change one thing at a time and test and prefer to do reversible things first. Often my changes will go the wrong way and need to be reversed. Eventually the carburetor will get attention. The article statement about airplane engines turning faster than weed eater engines is not consistent with my observation.

The factory torque and HP curves might be helpful is establishing a target RPM. Does anyone have a factory specification sheet?

Initial plan was to use 2 Ryobi’s on a 35# or so existing airplane. After running the engine it is unclear that two will fly the airplane. Time to rethink the plan and maybe fly it on something else.

The Ryobi is compact and well suited for model airplane use. I’m OK with the rod but the flywheel key is a horrible two-penny cost reduction. You undoubtedly noticed the #12 screws, which indicate the designer is an old fart (myself included). The rod however is unconventional indicating younger value orientated thinking. A similar design with twice the displacement would be much better. Power to weight changes drastically for the better as the displacement goes up.

Bill