so yesterday i had to push my 88 fourtrax about a half mile because it vapor locked on me and would not start back up... untill i pulled it into my garage. [img]i/expressions/face-icon-small-mad.gif[/img]

anyways.... today i went to look at checking the carb for clogs, or the gas cap for clogged vents or whatever and i found that there is a selector on the cap..

I had it in the off position.. is this a vent selector or something?

 

i do think that would do it. I think that allows air into the tank as fuel leaves. Kinda like putting your finger over the top of a straw.

 

why would they even give the option to un vent the tank?

 

I would guess the off position is intended to reduce the possibility of gas getting sloshed out when trailering, or whatever.

Honda generators also often have that feature.

 

so in essence it is a vent on/off switch?

 

I believe so, yes.

 

cool thanks. well i rode her around abit today with the switch set to "on" seemed to run just fine. but then again, its ran just fine in the past with it set to "off" as well. im lost. Im thinking vapor lock. but where the problem is has got me baffled.

 

I've fogotten to turn the cap valve on with my generator before.

It will run for quite a while until it starves out and stops.

If air can't get in to the tank to replace the volume of the gas as it burns, it eventually has enough of a vacuum to not flow fuel.