2) Water in Skymaster Fuel Tanks

If you still have the old thermos bottle type fuel tank caps, it may be time to replace them. Water in the fuel tanks could potentially cause engine failure in flight. Cessna developed a Service Kit (SK337-40C) that provided all the parts necessary to install new type fuel tank caps, but Cessna no longer has them. However, we at Commodore Aerospace Corp have kits and parts. Our kits includes; new caps p/n C156003-0101, new tank opening adapters p/n 22128-1 that have a raised lip and smaller opening to eliminate putting Jet-A hoses in the tank, top wing tank cover door assembly p/n 1522129-1, copy of Cessna drawing and some placards while they last. The new adapter is riveted with blind rivets around the fuel tank opening and sealed with sealant. Make sure the small scupper drain hole is not blocked off. We put a “Tootsie Roll Pop” stick inside the scupper drain hole while applying sealant to keep sealant out of the hole. We also still have a few new old style thermos bottle type caps with new rubber seals p/n 1426010-3 while they last.

Another problem that we have seen is that the scupper drain tube that runs thru the inside of the fuel tank can be ruptured or leaking. The only way to tell is to blow air into the scupper hole, while moving a piece of wire with some yarn/thread attached to the end along the scupper tube inside the tank. If you can see any movement of the yarn/thread, there is a hole in the scupper tube and the tank will have to be repaired or replaced. We have all new and/or good used fuel tanks and all associated Skymaster fuel system parts.