Can I remove the sediment bowl on my TO-20 to clean the filter as long as the fuel tap is
off? September 18, 2016.
Yes, that’s the way you’re supposed to do it. Close the fuel shutoff knob and then loosen the bail to remove the bowl. You may need a new gasket however, The gasket is the same as that used on early Ford tractors and many others.
After removing the bowl remove the filter which could be a brass screen or a round, stacked disc filter. In the case of the stacked disc filter, it will unscrew when you turn the bottom counter clockwise. Carefully wash the stacked disc filter in solvent like mineral spirits or spray brake cleaner. The operator’s manual used to say wash it in gas but that is considered dangerous today. Try not to let the discs come apart, hold the assembly by the threaded top screw. If the sections do come apart, just restack them. It’s also a good idea to open the valve a bit and let some gas run out of the assembly into a can before reinstalling the filter or screen.
Keep in mind the assembly has two stand pipes inside the tank. When you open the valve two turns you are drawing from the top pipe which is drawing gas from above the bottom of the tank. It’s meant to leave a reserve gallon in the tank to get you home if you run out of fuel in the field. Opening the valve all the way will draw from the lower stand pipe which is still not drawing all the way from the bottom of the tank.
To get the last bit of fuel out of the tank and flush it, which you may need to do, you have to unscrew the assembly from the bottom of the tank after draining as much fuel as you can with the valve in the full-open setting. If there is water or dirt in the bottom of your tank you may have to do this. If there is gummy residue in the bottom of the tank you will likely have to remove it, and have it professionally cleaned at a radiator shop as they usually clean and repair fuel tanks as well as radiators. There are also some solvents you can try at home.
Flush the fuel line by removing it at the carburetor, and opening the fuel valve after you have the bowl reinstalled. Then put a spare flare fitting in the elbow on the carburetor, and carefully unscrew it. You should find another cylindrical screen attached to the elbow which you may also need to clean. Reinstall the elbow and screen, and then remove the drain plug from the bottom of the carburetor. Open the fuel valve again, and drain and flush the carburetor.