I really appreciated all the responces given. Here is where I am at now. Swapped the 16x8 prop for an 18x8 wooden prop. Carried the engine to the field for testing this AM. I figured that the neighbors have heard it enough. LOL. Idle slowed to below 2300 with the larger prop. Yea!, but engine still died after about 30 seconds at idle. Made very minute adjustments to the low speed needle to richen it and "Walla" she idled like she should. Transition was also good.I got almost 6900 RPMs with the 18X8 prop on the test stand with only about 20 minutes running time on the new ring. I will swap it out with the Ryobi in the plane that srill has the stock carb on it. I'll wind up with a net gain of between 700 and 800 RPMs with the same prop. I will see how this will fly my Giant Super Sportster. Thanks again for helping me with my problem. Pat