Quarter Turn Gas Caps

[D45]

Does a leaky quarter turn gas cap mean I need a new one? Or is there a trick to having these seal better?

The gas cap gasket appears to be fine

I'm working on a 3.5HP Briggs edger

While the engine is running, theres no leak.

As soon as it gets shut off, gasoline leaks out of the mounting area for the quarter turn

125-178 is the Stens part number

494559 is the Briggs part number

 

[zimman]

Wrap the entire engine in foil due to vapor lock. LMAO
Kidding of course.
Maybe a gasket in the cap? Put a new cap on it.
Zim

 

[D45]

The gas cap gasket appears to be fine

^^^^^^^

I'm cheap, was trying to save $10

I'll order a new cap

 

[zimman]

^^^^^^^

I'm cheap, was trying to save $10

I'll order a new cap

Me too but you don't need a fire. LOL
Zim

 

[D45]

New cap installed...... .same issue

 

[Fav Onefour]

Trying to figure out why a gas cap would have liquid pressure? Are you tipping the machine over when it's off?

 

[Stuart in MN]

The gas cap should be on top of the tank so I can't envision how it would leak, unless the edger is laid on its side or something. Is it getting hot enough for the gas to expand and pressurize the tank, or are you overfilling it?

 

[gahrajmahal]

Heat from running the edger is causing the tank to expand. While running, the carburetor handles the built in pressure. When stopped, there is no place for the fuel to go. See what happens if you stop once the tank is empty or near empty. Intentionally position so gas cap is highest point when shut off and stored.

I have a Husqvarna leaf blower that suffers the same malady. In summer when blowing grass from the sidewalks after putting it up it has a fuel smell. In the fall, when colder outside and I stop blowing leaves when the tank is empty, no smell.

 

[4xdog]

While running, the carburetor handles the built in pressure. When stopped, there is no place for the fuel to go.

Why wouldn’t fuel pressure be released through the carburetor even without the engine running? If the fuel supply line valve is closed, I guess the pressure could build up in the tank. Perhaps thr float bowl valve would force pressure backwards?

 

[gahrajmahal]

Why wouldn’t fuel pressure be released through the carburetor even without the engine running? If the fuel supply line valve is closed, I guess the pressure could build up in the tank. Perhaps thr float bowl valve would force pressure backwards?

It’s just my hypothesis and observation. I have replaced my fuel cap twice and fuel hoses twice, plus the primer bulb. It seems better when I run the tank empty, compared to in the summer when the tank is fuller when I shut it off cause cleaning off the driveway and sidewalk doesn’t take a full tank of fuel. It hangs so the fuel cap is the highest point.

 

[D45]

Definitely not overfilling it and not tipping it on its side

Leaks gas, just enough to coat a small area, but shouldn't leak.

The is coming out from the bottom of the gas cap area where it meets the metal tank

 

[BurtEggley]

does it do it if you leave the cap a little loose after running it? Or since it is a metal tank, could there be a crack where the spout is brazed to the tank?

 

[Codyboy]

Definitely not overfilling it and not tipping it on its side

Leaks gas, just enough to coat a small area, but shouldn't leak.

The is coming out from the bottom of the gas cap area where it meets the metal tank

Tank neck is bent or damaged. I had an old motorcycle 1978 XL75 with a steel tank. The hole got bent just slightly somehow and it never would seal after that. I tried prying it back flat but had to replace the tank.