gastank vent

[jmk]

Can closing the vent on an external tank over a long period of time, (month) cause the diaphragm in the fuel pump to stretch? Do you normally leave them open even in the rain? This tank was also exposed to the suns heat and also the tube in the inside fell off while sitting. Does the gas tube inside have a check valve to keep from losing the prime?

 

[roscoe]

Re: gastank vent

check valves are in the primer bulb.

Edit, brain fart. I was reading this all wrong and imagining my setup, which has a fuel shut off on the fuel line, to prevent flooding, as has happened in the past.

 

[foodfisher]

Re: gastank vent

If the floats and needle valves in the carb are working, I can see pressure from an overheated fuel tank, in a filled system, stretching the pump diaphram.

 

[john from md]

Re: gastank vent

Fuel pump diaphrams are made of fabric reinforced rubber. They are made to stretch within their design requirements. If they don't they won't work. Over time, they do wear out and need replacing. But that is after thousands of back and forth cycles.

Your concern is misplaced as far as shutting off the vent is concerned. You should be concerned that pressure in the tank does not push off a fuel line or even rupture the tank. Especially the external tanks as their plastic is known to expand and rupture at the seams.

John

 

[jmk]

Re: gastank vent

The fuel line inside the tank did come off. I don't know if it was because it wasn't on right to began with or if the pressure could have got to it. If there isn't a check valve in the line it couldn't have been effected by the pressure so it must have come off from the drive to the lake? I can't figure out how to put it back on either. Do the fittings on the tank come off so I can reattach the line to it?

 

[john from md]

Re: gastank vent

Email me a picture of your fuel tank and I will tell you how to repair the pickup.

As to check valves, there are two in your fuel bulb. They allow the fuel to only flow one way when you pump the bulb.

John

 

[jmk]

Re: gastank vent

I figured out how to change the pick up tube. The elbo unscrews out of the tank. The clear gas line broke off right at the end of the brass nipple. I have some snowmobile gas line that's that size I can put on it. Thank's for the help.