Should I see an air bubble in the fuel filter?

[Calabrio]

This fuel system problem has been defeating me for a month now. I have what looks to be a pre-89 Mercury outboard, with a 2.0 liter V-6 motor.<br /><br />I have replaced all of the fuel lines from the tanks to the carb.<br />I have rebuilt the fuel pump.<br />I have installed new filters.<br />I have replaced the 3 way switch regulating the tanks.<br />I have replaced the primer bulb.<br /><br />Before the fuel pump, and after the primer buld I installed a clear, glass fuel filter. Should this always be a solid blue/green color while the boat is running? Because, shortly after sharting the engine, a large air bubble will appear in there. <br /><br />When I operate the boat at high RPM's, shortly after it will die, seemingly starved of fuel. <br /><br />On the outside of the old style fuel pump, on the case that houses the metal screen filter, there is a screw that goes through a small rubber o-ring. I believe I remember seeing a small plastic washer in the fuel pump kit, but it was lost. Do I need to place this plastic washer over the rubber o-ring, and then put the screw through them both?<br /><br />And final question, is there a SLICK 50 like product for 2 stroke outboards.

 

[rodbolt]

Re: Should I see an air bubble in the fuel filter?

Hello<br /> yes a bubble there is normal. I just had a boat in for service that the clear glass filter was not capeable of flowing enough fuel. after a 2 mile run the fuel restriction alarm would trigger. I dont like the clear glass filters on large outboards. the plastic washer you talk about goes under the bolthead that holds the filter housing to the pump. check your fuel draw tube in the tank or run the motor on a known good portable tank with at least a 5/16th fuel line. I find many tanks that used a sceen wire filter in the draw tube. a nice idea that bites.<br />Good luck and keep posting

 

[Calabrio]

Re: Should I see an air bubble in the fuel filter?

That plastic washer is not in place? Is it important I find another one and put it in place? And. does it goes beneath the bolt head ontop of the o-ring? Could air be coming in from this point?<br /><br />Are you thinking that maybe the metal screen in the draw tube is becoming obstructed, or obstructing the flow itself? If I remove the screen, will any debris be stopped by the filters before reaching the engine. I can see quite a bit of crap being caught in my filter while running on this tank.

 

[greasemonkeyozi]

Re: Should I see an air bubble in the fuel filter?

Of course put an O ring there, you can buy Oring kits at a car parts store. Air will seep inside that housing. That screen is a waste of space on a motor, but its there and you gotta deal with it. Your filter wil catch the trash first. Even the smallest pieces of trash can pass through that screen. Whenever you buy a fuel filter, blow through it and make sure there is not much restriction of flow. I had that problem, bought a filter 2 small so I just bought ona a little bigger. Its not a see through, but its a filter, and its there. As you have seen, there are a big variety of filters at the parts store, just pick out a biggder one.

 

[Calabrio]

Re: Should I see an air bubble in the fuel filter?

The O-ring is certainly in place, if it were not there, gas would literally be spraying out. My question is, does a small, flat, washer go ontop of the o-ring? <br /><br />And, I might try removing the screen from my draw tube in the gas tank. It might be sucking up sediment, and causing an obstruction when the suction from the engine is great. Hopefully, the series of installed filters will catch anything that will now make it past the screen. On the upside, at least whatever crap may be there will be drawn out of the tank.....