fuel tank pressure

[Bucko250]

I have a 5 gallon plastic tank for a 25hp Johnson and after running for about 15 min. the bulb will deflate. The vent on the tank is open and when I tank the fuel line off and press the inlet in, the bulb will reinflate. When I try to pump the bulb it stays deflated until I press in on the inlet. Any ideas on why this is happening? It only does it when the motor is wide open and pulling a lot of fuel.

 

[s1jor]

Re: fuel tank pressure

sure the vent is clear from gunk

 

[jtexas]

Re: fuel tank pressure

It pumps up for you to start it, right? Does the motor stay running all right? When you say deflate, you mean it gets sucked in like my stomach at the beach when a babe walks by? Or just that it doesn't stay firm? Does it pump back up after you stop the engine without disconnected from the tank? It's not a pressurized system so the bulb don't stay hard while it's running but if it gets sucked up sounds to me like an obstruction upstream from the bulb. Between the tank end and the bulb. Not obstucted enough stop all the gas flow, only at WOT.<br /><br />and welcome to iboats<br /><br />p.s. it's not one of those 2-line hoses, is it?