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Subject: Gas Leak

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Frank (WNY)    Posted 09-25-2019 at 13:04:34 [URL] [DELETE]        [Reply] [Email]  
  • Gas Leak
  • I smelled gas in the barn so, looking at the carb, the outside was wet. It looked like it was coming from around the gas line flange fitting going into the filter screen elbow. I cleaned and rebuilt the carb last year and replaced the elbow, but not the gas line, so a leak around that fitting was not too surprising since I have had to crank it down before. I disconnected the line from the elbow with the shutoff closed. (I always close it when I shut down the engine. It dripped every few seconds. I opened the valve and shut it off and it still dripped. The valve assembly was replaced 2 years ago with a new one from Just8N's. Anyone else seeing this with the new valves?

    StormCloud601    Posted 10-01-2019 at 20:28:48 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Gas Leak
  • Could be some trash in the valve or as in my case, a friend of mine (with hands like country hams) turned off the gas and cracked the seat.

    Tim Daley(MI)    Posted 09-25-2019 at 17:49:25 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Gas Leak
  • The main causes of fuel leaks are #1, #2, and #3 sediment bulb valve stem. The only working part in the system, it will wear out the seal on it and leak. It is OEM Ford part number APN-9194 and costs $6-$8 at reputable dealers like just8Ns.com. If you pay anymore than that then they are ripping you off. #6 failure is from worn, cross threaded, or wrong fuel line fittings at sediment bulb inlet and/or at brass elbow carb inlet, SEE LINK for new OEM exact fuel line. FITTINGS ARE SPECIAL UNS 7/16-24 USED ON BRAKE AND HYDRAULIC LINES. Using plastic, copper, nylon, or rubber FUEL LINES is NOT recommended. Leak #4 comes when fellas leave the fuel valve knob on when they shut down the tractor. If seal is getting bad, it will leak if left ON and/or when opened. Leak #5 can be caused by backed up vacuum in stem if gas tank vent is plugged, can be caused for same reason if brass fuel line inlet at carb is plugged at the filter.

    #1. OEM FORD APN-9194 SEDIMENT BULB & VALVE STEM VIEW DIAGRAM:

    #2. APN-9194 SEDIMENT BULB FUEL VALVE STEM:

    #3. OEM SEDIMENT BULB ASSEMBLY & VALVE STEM:

    #4. OPEN VALVE STEM 2 FULL TURNS FOR MAIN OPEN POSITION, FULL FOR RESERVE POSITION, OFF POSTION WHEN NOT IN USE:

    #5. GAS TANK VENT PLUGGED OR FUEL INLET ELBOW SCREEN PLUGGED, MAY CAUSE NO-FLOW:



    #6. FUEL LINE; SEE LINK BELOW:

    Frank (WNY)    Posted 09-26-2019 at 12:31:08 [URL] [DELETE]        [Reply] [Email]  
  • Re: Gas Leak
  • Thanks Tim and Kevin, I have been buying all my 8N parts from Just 8N's because they are so knowledgeable like you guys. I probably should have bought a new fuel line when I replaced the valve, then again, when I rebuilt the carb and replaced the inlet elbow. I guess I will place a order for it and buy another valve in case the leaky valve turns out to be something other than junk in the fuel that became lodged in it. That way I can replace the stem first and if that doesn't work I will replace the whole valve assembly. Also, the gas leaking around the carb destroyed the hose from the air cleaner, so I will get a new one of those too. Thanks again, Frank

    Tim Daley(MI)    Posted 09-26-2019 at 16:46:07 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Gas Leak
  • That is the point - no need to buy a whole new assembly unless it is really old and you want to replace it or threads boogered but only buying a new one not knowing if it's defective is unwise. The working part is the valve stem and the part most likely to fail. The assembly has the two screens which are replaceable but if the threads are boogered up, it's scrap.

    Tim Daley(MI)

    K.LaRue-VA    Posted 09-25-2019 at 17:40:26 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Gas Leak
  • A leaky valve could just be grit from the tank preventing it from closing. Flush a quart or so thru the system and out the carb bowl. That may clear it. Look for stuff in glass bowl. That is a good sample of whats loose in the tank.

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