Vapor Lock? By t84a (Read 4,119 times)

[t84a]

So I'm still trying to sort out my new scooter and here's my latest issue. The thing cuts out after about 2 minutes. You can tell its fueling because you can smell it lean out. Suspecting vapor lock, I opened the cap and put it back on and it started right back up. Rinse and repeat. The cap is not vented but I believe the device pictured below does the venting. Can anyone shed some light on my issue. Its a GY6 169cc. Thanks

[t84a]

It will run all day without the gas cap so it has to be a clogged or bad cap.

[Bashan]

That thing in the picture is your vacuum fuel valve. It opens the fuel to the carb when the engine provides a vacuum, it has nothing to do with your problem. You are correct, it is a venting problem. You will probably find a vent line coming off of the top of the tank or side of the spout. It probably runs to a check valve and then a canister. Unhook the line from the check valve, stick a cheap filter in the end to keep dirt out, and tie it off high enough that gas doesn't slop out AND no loops that would allow fluid to block the venting. That will fix it. If there's no vent line it's a bad cap, you can drill it or replace it. Rich

[cyborg]

Had the exact problem with my et4 Vespa ,, drilled a tiny hole in the cap ,, the problem disappeared

[Alleyoop]

Check if you have an EVAP system of so here is how to take it off and have a good vent for that gas tank. IF YOUR scoot does NOT have a EVAP system then drill a 1/16 hole through the handle of the gas cap or the center of it.
Alleyoop

scooterdoc.proboards.com/thread/9954

[Guitarman]

A sixteenth is kinda big don't you think? Might let water in. A 32nd should be good.

[t84a]

Not sure what size I used but my cap is under my seat so I'm no ttoo concerned with water.

[jct842]

I drilled a 1/16" hole in the gas cap on my ford tractor.....cured it of same symptoms, it cut out after 5 to 10 min depending on how hard it was working and how full tank was.