Oliver dos'nt run well

I also live in Northern Wisconsin and plow snow with my 1650. I doubt icing is the problem. The fact that the engine seems to runs better with the oil bath air cleaner disconnected tells me that you are on the right track. There is some restriction in it that causes a rich condition. I'd try a new element and a lighter oil first.

Two other things I've learned. I run a bottle of STP water remover in each tank of gas during the winter. Also, be sure your ignition system is right on the money. I too had a problem with mine loading up during the winter. I replaced the points, plugs, plug wires, rotor, cap, and condenser... end of problem.

1 - Make sure the tractor has a thermostat installed and it's working. I've found 180 deg (or 192 deg if you can find one) is best for winter operation.

2 - Block off about 90% of the radiator front with cardboard, a plastic feed bag or whatever. Then pull the air inlet tube off the carburetor. This results in hot air from the radiator being drawn directly into the carb - eliminates any possibility of icing once the motor warms up. If it's dusty and you don't want to disconnect the aircleaner (not likely when plowing snow!), run a flex hose from the air cleaner inlet stack - position the open end right behind the fan to pick up the hot air.

Sometimes installing spark plugs one or two heat ranges higer helps too. Seems to me I've got Champion N-14Y in them all now.

Hope this helps!