fuel leaking from primer bulb

Discussion in 'Mechanic and Repair' started by awerking, Nov 9, 2008.

  1. awerking

    awerking LawnSite Member
    Messages: 1

    Hello all - need some help diagnosing a problem.

    John Deere JS63 self propelled lawnmower - 6.5HP Briggs & Stratton motor (model series 121602).

    Mower has been in storage for about a year and a half since we relocated and did not have a yard to mow until we moved out of the apartment and into our house.

    Here's the problem:
    I got the mower ready to go today - fresh oil, new plug, checked the airfilter, and filled it with gas. A few seconds after putting gas in it I noticed fuel shooting out of the small hole on the front of the primer bulb. The mower was on a slight incline in the driveway, so at first I thought that maybe that had something to do with it. I moved the mower to level ground and the fuel continued to shoot out of the primer bulb.

    I pulled the fuel line off and plugged the end so I could investigate. I removed the air filter cover and filter, and could see fuel pooled in the bottom of the plastic housing directly in front of the primer bulb. I removed the filter housing assembly from the carbeurator, but could not see anything unusual inside the carb. I reattached the fuel line, and gas immediately began pouring out of the carb.

    I'm guessing some sort of seal, needle etc. disentigrated or went bad while the mower was in storage. It was stored without gas, although I did not verify that the bowl on the carb was completely emtied of fuel before putting the mower in storage.

    Any idea what might be the cause of the problem? Any help, direction, or suggestions would be greatly appreciated.

  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    You need to remove the carb then take it apart, Clean it up well with carb & choke spray cleaner shooting it through ALL ports and passages. If just cleaning doesn't solve the problem replace the float needle valve inside the carb.

    Also assure any holes/ports in the bowl retaining nut are open as well.
  3. jgarner

    jgarner LawnSite Member
    from nc
    Messages: 6

    I agree that you need to clean the carb. I would also replace the primer bulb. They tend to deteriorate and leak over time.
  4. Grouch

    Grouch LawnSite Member
    Messages: 36

    The needle seat has deteriorated and will need to be replaced. Happens to units set up too long with fuel left in them, plus the alcohol in fuel these days isn't helping. Your dealer will have a needle and seat kit and/or a rebuild kit. I recommend the rebuild kit as it will contain the needle and seat, bowl ring, and other items.
  5. I.M. Green

    I.M. Green LawnSite Member
    Messages: 177

    rebuild carb and replace fuel lines and bulb while you're at it...

Share This Page