Originally Posted by
1QwkSport2.5r
If it's ringed, it's likely a .45. The .46's were ABC, the .50's were all ringed but stamped I believe. Has an EZ carb I think. The .45 and .50 liners have punched ports, not machined. The bore of the .50 is .906".
I was tempted to remove the head to check the bore, but I figured to run it first. If no problems with the engine, I won't open it up. I have it soaked in Marvin's Mystery oil now. I compared it to my Irvine 40. The Irvine 40 is longer due to the 2-piece crankcase and tilted carb, but the Fox cylinder is considerably wider and taller, so definitely bigger engine.
The previous owner said it came with the MKx carb, but he is fixing it right now. I put in my spare EZ carb for now. I hope to bench test it this weekend without muffler. What is a good prop to start with? 10x6 or 11x6? I also have a 12x4 and 10x8.