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- Jan 4, 2011
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Has anyone here built an Atkinson Differential using the design by Brooks Pendergrast? I built one using the Gingery plans a few years ago and was never able to get it to run so I decided to try the Pendergrast design. So far it I am having better luck on this design but I am having a problem with the engine running for about thirty seconds and flooding out. I can blow out the cylinder and clean the spark plug and it will run again for about 30 seconds. I am wondering about the intake port into the cylinder. Pendergrast says that a spacer is required on the valve so that it does not get sucked into the cylinder but the drawing shows a .250 hole through to the cylinder and a .375 dia. valve is not going to be sucked into the cylinder through that hole. I am wondering if that hole should be larger. The carburetor adjustment is extremely sensitive and the mixture is apparently not the best.
