The Massey 1650 started losing power and surging, barely running. I replaced all the fuel lines and filter sprayed some carb cleaner in it and she ran for about thirty more minutes, before returning to the same state. I thought about replacing the fuel pump, but I really thought the carb was the problem, especially after seeing how much fuel the pump was throwing with the line disconnected. I pulled the carb and soaked it some Naptha, pretty hot stuff, and got the gunk off the outside. I took the bowl off and what do I see but a wad of looks like caramel, but hard like caramelized brown sugar, looks like the PO was using the old ethanol gas. I took all the jets the float and everything apart and soaked it for an hour, then used a pipe cleaner and air compressor to remove any residue. I may have to buy a new bowl VERY soon, the spot where the caramel was has been eaten away more than halfway through the bowl, I got it back together and running much better, now I'm going to consult my service manual on the correct needle/jet/screw settings.