Hey guys - my spring project is getting my Jacobsen G-10 tractor running after it blew a head gasket last fall. I had it idling one day and all of the sudden it started losing power and running erratically, popping and blowing oil out the exhaust. The #2 and #3 cylinders had 0 psi. I pulled it apart and there was a clear chunk of gasket missing. I took the head to a machine shop and had it compression checked, hand magged and planed. I replaced it and the head gasket obviously. I did not do anything to the valves since they seemed fine. I also had the intake exhaust manifold brazed. I reassembled the engine in the past couple of weeks and made the first attempt to run it today. It started right up however it is running extremely erratically in bouts of power loss then running with puffs of black smoke. It smells very gassy as well - choke is wide open. I checked the compression - I have 155 lbs on all 4 cylinders. I suspect the carburetor since it was sitting all winter and was on my bench for a month while I had the engine stripped down. I took it apart but nothing visible. The float seems to operate the float valve ok. I didn't check it for holes though. I tried bottoming the idle fuel needle and opening it to its initial setting also - no change in performance.
Does anyone know this engine that might have some suggestions? I'm stumped. Thanks in advance - Jon