I bolted the new to me 101B to the bench, put a recoil starter on it and checked the compression - a consistant 62 psi. Changed gauge to an old one that always reads about 30 psi lower and sure enough all I could get was about 30 psi. Rings are free, piston and bore look good. I don't hear any leaks around the sparkplug hole. I have contacted the seller and I am waiting on his reply before I open it up. Any thoughts? Seller described the motor as: "McCulloch 101B that should be ready to run. Has a fresh bore and piston. Has been run on the bench, but no time on the track or road. No carbon build up on the piston. Head shroud is aluminum, and has cracks, but no dents. Could be fixed to show condition easily. Comes with the double pumper carb, super stuffer, and chain guard. Crank is keyless and has left hand threads that are in excellent shape. No disappointments." I am hopeful there is some simple to fix problem.
Ron
PS Many thanks to the one(s) who said to always leave on a loose flywheel nut when removing a flywheel. That baby popped and made me jump but it stayed nice and safe on the shaft.