Kymco Agility 125- Fuel leaking out of the air box-FIXED!!!

Discussion in 'Battle Scooters' started by wheezyryder, Aug 18, 2015.

  1. wheezyryder

    wheezyryder Punk in Drublic

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    Hello all. Some of you may have peaked in on a thread I started about the same scoot a few days ago. Finally got my idle issues sorted out. Been riding around for a few days and I guess the Kymco decided it needed some more attention.

    Rode up to the grocery store today and when I came out I noticed the strong odor of gas. Looked down and saw a fair sized puddle on the concrete and fuel dripping out of the bottom corner of the air box. Removed the airbox cover and the air filter (which was partially soaked in fuel) and saw a small stream of fuel running out of the air inlet tube that connects the airbox to the carb. I removed the air filter, reinstalled the airbox cover. Wouldn't start. Drained the fuel out of the float bowl via the drain screw, opened the throttle wide open and was able to get it to start. I was glad because it would've been about 3/4 mile partially uphill journey to push it home.

    I suspected either that the carb float is stuck in the open (down) position or that the vacuum operated fuel petcock isn't functioning properly. To test the petcock I disconnected the fuel line at the carb, attached an extension to the line and routed it downward to a gas can under the scooter. Fuel started trickling out at a slow but steady drip. At this rate I think it will empty the mostly full fuel tank in an hour or two.

    Does anyone know if this is abnormal for the petcock? Should it allow a bit of fuel past it without the engine vacuum or should it be completely sealed? Is the carb float supposed to provide further seal to prevent the fuel from draining down out of the tank?
    #1
  2. Jim Moore

    Jim Moore "You ain't black!"

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    Did you fill it up with gas to the very top right beforehand? You gotta leave about a half inch of air in the tank. Somewhere in the manual it says "Don't top off tank." They mean it.
    #2
  3. YamRZ350

    YamRZ350 Been here awhile

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    I can't speak about this model specifically, but I think you have both problems. The petcock is leaking and the float valve isn't sealing allowing the carb to overflow.

    In the old days, there was an overflow tube in the carb that directed the fuel directly to the ground in case of this exact problem. Sadly, newer stuff doesn't have that and fuel just pours into the engine or airbox or both.
    #3
  4. Dan V.

    Dan V. Been here awhile

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    Sometimes the petcocks go for no apparent reason - perhaps alcohol degrades the diaphram. Check Treatland to see if they have replacements in the Secret Scooter section.
    #4
  5. wheezyryder

    wheezyryder Punk in Drublic

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    Jim I had filled the tank the day before and probably ridden about 20 miles or so. I'm pretty sure it wasn't an overflow.

    Yam and Dan I was wondering if both the petcock and float had failed. I'm not surprised that the petcock failed. It sat with E85 fuel in contact with the diaphragm for 5+ years without moving. You think the float may have stuck also? I'll take the carb apart and check it when the petcock arrives. Is there anything I can do to prevent the float from sticking in the future? Polish the float pin or something?

    Also, after I got home I thought about the fact that fuel may have overflowed into the crankcase. I'll drain the oil and see if it smells like gas. That oil is new since I got the scoot about 300km ago but I wanted to changed it at a pretty short interval anyway to flush out any funk that may have collected from sitting motionless for so long.
    #5
  6. YamRZ350

    YamRZ350 Been here awhile

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    Inspect both the needle and seat for damage. Some needles have a viton tip and they can deteriorate over time. Inspect the float as well, they can and do get damaged and need adjustment or replacement. I've seen engines so full of fuel that they "hydro" lock and cant turn over. If the inlet valve was open, there's no way there's not fuel in the oil. It would be a good idea to change it.
    #6
  7. wheezyryder

    wheezyryder Punk in Drublic

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    I inspected the float needle but now that I think of it I didn't inspect the seat. I'm off of work tomorrow so I might pull the carb apart then. That way when my new petcock comes in I can just slap it on and go. This is the first non-runner I've ever bought and my first scooter. I've enjoyed the experience of troubleshooting and getting it back running but at this point I just want to ride the damn thing! It's great for getting around Atlanta where the roads are congested and the parking is scarce.

    I'm already planning a few farkles. L.E.D. fog lights, custom lever guards ( bark busters) and frame sliders. But I won't start farkling till I get all the bugs worked out and it runs reliably for a month or so.
    #7
  8. Dabears

    Dabears Long Timer

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    You may already be aware, but when you have a fuel leak like you describe fuel often gets into the crankcase. Pull your dipstick and if the oil level is high or it smells of gas change it immediately.

    You don't want to run that motor if the oil has been contaminated by fuel.
    #8
  9. YamRZ350

    YamRZ350 Been here awhile

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    You'll get it squared away. There's nothing as satisfying as rebuilding / bringing something back to life yourself. Fuel systems can be a challenge.
    #9
  10. wheezyryder

    wheezyryder Punk in Drublic

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    Looks like you were right YamRZ350. It was both problems.

    My new petcock came in yesterday so I replaced that. No big surprises there.

    When I took the carb bowl off I did get a bit of a surprise. I found a few specks of trash in the bottom of the float bowl. After removing the float (which was moving freely not stuck at all) and float needle I found a speck of trash stuck to the fuel port that the float needle fits into. It was right near the opening in just the the right spot to prevent the needle from being able to seal the port. The reason that is a surprise is because I've had the carb apart at least three times to clean it out. I flushed out the fuel tank and replaced all the fuel lines and fuel filter. I would've thought that with all that cleaning plus the screen on the petcock and the fuel filter it would eliminate trash in the carb. Maybe there was a bit of trash stuck in some deep recess of the carb that shook loose after riding for a while.

    Also changed the oil while I was at it. It didn't smell like gas and I didn't see any obvious signs of contamination. Not sure if gas is more or less dense than oil and thus would be on top or bottom of the oil?

    Thanks again for everyone's help and suggestions. For now it's running great again. Rode about 25 miles yesterday. Hopefully the spirits of motorbike maintenance are appeased for now.
    #10
  11. YamRZ350

    YamRZ350 Been here awhile

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    Good news!
    If dirt in the carb continues to be a problem, you might want to think about an in line filter. There are very compact versions out there that work well.
    If your motor happened to stop at TDC with the valves closed, it's possible that no fuel got into the engine. (Run out and buy a lotto ticket right away...)

    Again, congrats.
    #11
  12. wheezyryder

    wheezyryder Punk in Drublic

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    Part of the reason that I'm puzzled is that I did put a in new inline filter at the same time I flushed the tank and replaced the fuel lines. It's a mystery.

    And I will head out right now to go get that lotto ticket. I'll take the scooter :)
    #12