Evaporative emission control By kimdabe (Read 1,364 times)

[kimdabe]

I recently purchased a BMS Heritage 150. When I fill the tank, I noticed a fuel leak. After a little research I found that it was coming from a canister identified as a "charcoal canister", more formally called the Evaporaive Emission Control System. That said, when the gas tank is full, and the scooter is sitting in the sun the leak was noticed. I thought that it might be an overflow, but it continued after I ran it for 10 miles.  If I take the gas cap off, the leak stops. Can one of you guys solve this problem. Kim Dabe, Cincinnati

[Bashan]

Did you fill it past the bar at the bottom of the spout? Don't. Where is the leak coming from exactly...can you tell? Are you new to scooters? I would be a little hesitant to have you remove the system yet. Don't fill past the bar and see what happens, we can go from there. Rich

[Alleyoop]

Yep, what happens if you overfill it the gas gets into the Vent hose and fills the Charcoal canister and then you will have gas dripping out of the bottom of the canister. If it blocks it up good your scooter will die because of lack of fuel if the tank is not venting it will stop the gas flow to your PUMP and or Petcock. If that happens crack the fuel cap open a little so the tank can vent.
Alleyoop

[rks]

If your gas tank is under your feet, (as I believe it is) you'll probably find the vent hose is located toward the left side of the tank. If so, I've found that it helps if you park your scoot on the center stand after fueling, rather than using the side stand...and as stated by others, don't fill past the metal bar...Bob

[kimdabe]

New to this forum and am finding lots of useful stuff. All three of you guys are great. I think that you are correct and that the tank was over filled. The gas was dripping from the smaller of the two ports on the canister. Now that the cannister is soaked with fuel, will it dry out and function as it was designed to do? Also, I suppose the trick to not filling the tank...and guess when it is full instead of allowing the auto shut off on the gas pump turn off the flow?

[Bashan]

Yeah, don't do that, it's always a manual fill job. The problem I could see at this point is a little check valve somewhere between the tank vent nipple and the canister. If it's loaded up with fuel you need to pull it off and clear it. If it's stopped up your bike will stall from an ever increasing vacuum in your tank. The issue of whether the canister is working correctly is moot...they never work correctly. You just want them to not shut the bike down. If you want to remove the vapor control system here's how it works:

Here's how you get rid of it...I do on all of my bikes:

[kimdabe]

Thank you for your reply and your excellent diagrams. For now, it is running just fine.. but the fix seems simple.