What was found
PILOT ENCOUNTERED LOSS OF POWER ON LT ENGINE AND MADE AN UNSCHEDULED LANDING. WATER WAS FOUND IN LT TANK AND LT FUEL LINES. WATER WAS SUMPED OUT, ENG TEST RUN, AC RETURNED TO HOMEBASE. LT SIDE CAP WAS FOUND TO BE LOUSY FIT, PROBABLY ALLOWED WATER TO ENTER. SWAPPING RT FUEL CAP TO LT WING MADE A SLIGHT IMPROVEMENT, NOT MUCH. (CAPS CAN NOT BE ADJUSTED) CAPS APPEAR TO BE THE PROBLEM, NOT THE GASKETS. AC IS KEPT IN HEATED HANGAR.