1991 225 evinrude strange fuel problem

[elwilliams13]

I have a 23 foot mako made in 1979. It has a main 90 gal. and a reserve 30 gal. tank. The engine runs great with the main tank but when I switch to the smaller tank and run over 3000 rpm it creates a vacuum in the line strong enough to collapse my primer bulb, but as soon as I switch over to the larger tank or run at low rpm it fills right back up. My guess is that the smaller tank is not venting properly. I have replaced 80% of my fuel line and my engines vro system is disabled so I premix @50:1. Can anyone please help me?

 

[roscoe]

Re: 1991 225 evinrude strange fuel problem

Have you checked the tank vent for any obstructions, mud daubber nests, crud, dead animal?

 

[ob]

Re: 1991 225 evinrude strange fuel problem

elwilliams,Also insure that the tank pickup tube strainer is not being restricted by suspended particulates in the tank itself.You need to know for sure that the tank is clean.

 

[Dhadley]

Re: 1991 225 evinrude strange fuel problem

Dont overlook the anti siphon valve in that tank.<br /><br />Good luck!

 

[Dhadley]

Re: 1991 225 evinrude strange fuel problem

elwilliams13 <br />First Mate <br />Member # 27299 <br /><br /> posted July 05, 2003 04:26 PM <br />--------------------------------------------------------------------------------<br />Dhadley is that on the inside of the tank or is it along the top. the tank is foamed in and would not like to remove it if I can help it. <br /><br />--------------------------------------------------<br />Please dont start another thread on the same subject -- its too hard to follow that way.<br /><br />The anti siphon valve cosists of a ball and spring inside the fitting the hose is attached to on the tank. Remove the hose and the fitting should unscrew from the tanks pick up tube. You can replace it or simply punch the ball and spring out. <br /><br />If the ball sticks it could act as a fuel shut off. <br /><br />Good luck!