Check the drain plug on the front side of the engine case (below the exhaust Y-pipe. Maybe the drain plug is slightly open/missing? Just because coolant "looks" like it is coming from the underside doesn't necessarily mean it is! The coolant could be running down one of the coolant hoses. Other places to check... the hose that attaches to the water pump below the carburetors (lower hose). Also, the hose that connects to your heat exchanger(s) (under the seat). Sometimes , those short hoses deteriorate and start leaking. Last check would be your water pump! The pump is a split design with gaskets between halves and sometimes will leak. Overflow tube from your radiator? Without standing in front of the sled... it''s hard to diagnose, but these places would be as good a place as any to start looking. Tory