I picked up a 1973 Glastron-Carlson with a AQ130C Volvo-Penta motor from a junk yard as a project. Had the motor rebuilt and after we started it, we found that the 2 middle cylinders aren't firing. The new plugs are sparking, both carb working properly, good compression in the cylinder, (125 psi+/-). Thought of a head gasket leak, but, no milky liquid or bubbles in the oil, and again, good compression. It has new distributor cap, points and rotor, and new coil. Thought the two lobes on the cam might be worn down in those cylinders, but lifters appear to be working as well as the other 2 cylinders.
Any help or suggestions would be greatly appreciated!!!!