fuel line collapse 98 merc 115

[captjack111]

the fuel line bulb collapses after about 10-15 mins of running at cuising speed and the motor runs rough and then shuts off. it runs fine at idle or with an auxilary portable gas tank. i have replaced the fuel separator and bulb and exterior lines but not main line from tank. is there something inline that would shut off the supply like a faulty oil level detector or is it just the line itself?

 

[j_martin]

Re: fuel line collapse 98 merc 115

the fuel line bulb collapses after about 10-15 mins of running at cuising speed and the motor runs rough and then shuts off. it runs fine at idle or with an auxilary portable gas tank. i have replaced the fuel separator and bulb and exterior lines but not main line from tank. is there something inline that would shut off the supply like a faulty oil level detector or is it just the line itself?

Something plugged in the line or tank. Could be plugged tank vent, plugged pickup screen, faulty check valve if there is one at the tank, or collapsed inner tube in the fuel line itself.

Fix it. If you keep running it till it balks, you'll finish the piston damage job you've already begun.

hope it helps
John

 

[captjack111]

Re: fuel line collapse 98 merc 115

thanks John,
I had not thought about damage to the rings, they were just replaced right before this started to occur. the gas line and tank are difficult to get to (inside center console)and I didnt want to waste my time if it could be something else. It'll be next weekends project. I love the old boat.