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Fuel valve leaking on my Cessna 150F
- Thread starter nganouu
- Start date
Brute Harry
Well-known member
My friends just leave the valves open all the time though...
AirmasterPilot
Member
Do you mean an external leak, or is it leaking past the valve in the "off" position? If fuel is leaking out around the selector shaft, it probably can be taken apart and repaired. If it is leaking internally so that when you select "off" fuel still goes to the engine, it is probable that the internal metal parts are worn and cannot be repaired.
If your plane is no longer supported by the factory and a certified replacement is not available from the usual aftermarket suppliers, the FAA allows you to determine what part can be used as a replacement as long as it meets certain criteria such as fit and function. No 337 field approval is required, just a sign off by an A&P. You may do it for your own plane only, you are not allowed to sell such parts to others. When the valve on my Airmaster was leaking, I found a valve intended for homebuilts at Aircraft Spruce that was almost an exact duplicate of the original from 1938, except that it did not have a "both" selection, and the inside cone was nylon instead of metal. By drilling one more hole in the cone at the proper location, we modified it to have left, right, both, and off positions. It was installed using modern AN fittings in place of the 1930's vintage auto fittings. A log book entry was made, and everything was good to go.
Look up the word VARMA for more info:
The FAA has approved a new program called the Vintage Aircraft Replacement and Modification Article program (VARMA), which will allow the use of certain off-the-shelf parts in type-certificated aircraft. The new rules apply to non-safety-critical parts used in planes weighing less than 12,500 pounds built before 1980.
If your plane is no longer supported by the factory and a certified replacement is not available from the usual aftermarket suppliers, the FAA allows you to determine what part can be used as a replacement as long as it meets certain criteria such as fit and function. No 337 field approval is required, just a sign off by an A&P. You may do it for your own plane only, you are not allowed to sell such parts to others. When the valve on my Airmaster was leaking, I found a valve intended for homebuilts at Aircraft Spruce that was almost an exact duplicate of the original from 1938, except that it did not have a "both" selection, and the inside cone was nylon instead of metal. By drilling one more hole in the cone at the proper location, we modified it to have left, right, both, and off positions. It was installed using modern AN fittings in place of the 1930's vintage auto fittings. A log book entry was made, and everything was good to go.
Look up the word VARMA for more info:
The FAA has approved a new program called the Vintage Aircraft Replacement and Modification Article program (VARMA), which will allow the use of certain off-the-shelf parts in type-certificated aircraft. The new rules apply to non-safety-critical parts used in planes weighing less than 12,500 pounds built before 1980.
Last edited:
George Coy
New member
- Joined
- Jan 27, 2025
- Messages
- 1
Having just last Sunday done one more of the C150 valve removal, disassembly, clean, reseal, reassembly and instillation. you need to remove the left, right "B: nuts at the "T" fitting as well at the outlet fitting. There are two AN3 bolts wit stand off/spacers that release the valve assembly. The removal and installation are all done by blindly.
once you have the valve assembly out, is easily disassembled for a good cleaning with Scotch bright. Remove the top brass cover, keep the order of the O-ring, washer, spring There are two little metal tabs (one on top of the other) that you need to pick out. They set the rotation stop positions of the valve. If it is frozen it may be necessary to heat the valve body with a propane torch get it apart. Reassemble with some EZ Turn (Fuel lube). The O ring at the top of the shaft is an MS28775-011. It pays to take photos as you disassemble so it will go back together properly.
once you have the valve assembly out, is easily disassembled for a good cleaning with Scotch bright. Remove the top brass cover, keep the order of the O-ring, washer, spring There are two little metal tabs (one on top of the other) that you need to pick out. They set the rotation stop positions of the valve. If it is frozen it may be necessary to heat the valve body with a propane torch get it apart. Reassemble with some EZ Turn (Fuel lube). The O ring at the top of the shaft is an MS28775-011. It pays to take photos as you disassemble so it will go back together properly.
