1978 Mercury 80 hp leaking fuel at engine inlet screen

Elkaholic

Recruit
Joined
May 6, 2011
Messages
4
When I squeeze the fuel bulb, gas shoots out around the screen cover. This has been happening since I bought the boat 7 years ago, but is worse now. I replaced the o-ring gasket previously and again to no effect. I'm wondering if a regular o-ring is the problem? Does it need a thick o-ring? I tried placing a washer between the cover and bolt to add pressure to the cover before the bolt bottoms out. It seems to me that the o-ring would have a hard time sealing the wire mesh screen area. The plastic cover looks to be okay. Any ideas???
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,549
The proper oring and screen come with a fuel pump kit. The oring goes on top of the screen, so the cover can contact it. There is usually a white plastic washer under the screw head. I would usually install the screw and rotate the plastic cup until it seats on the oring and then tighten the screw. It shouldn't leak.
 

Elkaholic

Recruit
Joined
May 6, 2011
Messages
4
I got a fuel pump kit. The o-ring is slightly larger in diameter and thinner than the one I was trying. Fuel is still leaking profusely when I squeeze the bulb. I don't think there is anything wrong with the housing. My next guess is it must be the plastic cover? It doesn't appear to be damaged. Maybe it warped when I had the extra washer next to the bolt head? Our local shop doesn't have anything that old. Thanks for the advice, Chris.
 

captain madness

Recruit
Joined
Jun 27, 2022
Messages
1
hello elkaholic
Hoping your still on here cuz I just bought a 78 mercury 800 and I have fuel spraying out around the cover. How did you end up fixing it? please I'd love the help. Frustrated
 
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