Gas cap Rubber O Ring keeps stretching on the Lifan 6.5?

[kevdawg]

I cant figure out why this is happening, maybe to much pressure? I have the 6.5hp Lifan on my doodle bug and everytime I go fill it up I noticed the Rubber O ring that is in the gas cap is stretched looking, almost oblong looking. Then when i go ahead and install it back on it does not seal properly because that Oring is squeezed out the side kinda.
Than i went ahead and left the gas cap off for a couple of days and that oring shrunk itself back to normal shape? This is weird, is anyone else having this issue, and if so what are you doing to resolve this?
thanks

 

[dobber]

I did not have that exact problem, but I got a new Cub Cadet Mower, It has been vacume locking the gas take and it won't restart when warm unless I take the cap off and blow in the gas tank. I took the first one I bought back to home depot do to it, but I think they all do it. Maybe your seal is getting sucked in do to the presher? I think I am going to put a small hole in my cap so it will release tank pressure.

Kelly

 

[musician1john]

I have a HF clone motor on a go-kart that has the same problem with the o-ring on the tank gas cap. Almost seems too large of a diameter to seal properly, leaks gas on the top of the tank. I'm wondering if replacing it with a new cap (Honda) may remedy the problem.

 

[kevdawg]

I have a HF clone motor on a go-kart that has the same problem with the o-ring on the tank gas cap. Almost seems too large of a diameter to seal properly, leaks gas on the top of the tank. I'm wondering if replacing it with a new cap (Honda) may remedy the problem.

Yes that is the exact problem I am having. I am willing to try another sleek gas cap as well. Were can we find one at or the Honda one at that will work on our 6.5 lifan tanks?

 

[kevdawg]

Do we need a tang style cap? Not sure what size we need though, 1 1/2 or 1 3/4?
Fuel Cap, Plastic For 4 Thru 8 Hp Engines, Models Gx110, Gx120, Gx140, Gx160 And Gx240 Tang Style Cap For 1 1/2&#34 Opening - 55-126 by: Oregon - Lawn Mower Parts

 

[musician1john]

I'd have to measure to be sure, the engine is at a friend's garage. The one in the weblink may work, for the price, it may very well be worth it to try. Mine leaks quite a bit and the angle the motor sits at just adds to how fast it leaks.

 

[Kenny1]

I just went to the shed and pulled the cap off of a gx120 thats been sitting there. The cap looks a bit different and the seal is thicker and the inside diameter is a little smaller. It fits the clone's cap perfect and seals really nice. The original seal is real sloppy. I think as you tighten the cap it gets crooked and isn't covering the hole in the tank. On the flip side, the seal off the clone seals on the gx120 tank just fine. Who knew.ut:

 

[Nitrohorse]

Preparation H help shrink seals...

 

[superior]

I found the way to fix the gas cap o' ring problem. Simply turn the rubber gasket upside down, leaving the flat smooth side to make contact with the tank. It seals in the groove inside the cap better without expanding. I just rode the living crap out of mine in the Oregon coast range today and not one drop of gas oozed out of the cap. Try it guys and let me know if it works for you too. I bet it does!:thumbsup::thumbsup: