​Rebuilt Carbs - is leaking fuel normal at Air Silencer Gasket?

sumocomputers

Petty Officer 2nd Class
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Feb 23, 2015
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Rebuilt the carbs on my '89 Johnson 70, and replaced all 5 gaskets. 3 between carb and block, 1 between carb and silencer, and 1 between silencer and cover.

I ran the boat a few hours after the rebuild, and inspected the inside bottom cover for fuel leakage, and it was spotless. We trailered the boat and of course tilted the motor up manually for storage.

Fast forward a week later, and now I have a fair amount of fuel in the bottom cover, and the source of leak seems to be at the gasket between the carb and silencer on all three carbs (see photo of gasket now removed). Also, the inside of the cover had fuel spray, and that gasket was also a little moist with fuel, so I think the fuel may have leaked from the bottom of that as well.

I installed all the gaskets dry, according to the service manual. I tried to tighten as evenly as possible when installing, and if anything I might have overtightened just a hair. No I didn't have a torque wrench.

So is this normal, or do I have a problem? I don't mind a little fuel if it is normal, but it just doesn't seem right to me. I have another new one of these gaskets if I need to do something different.

Thanks,

Chris
 

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Bosunsmate

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I wouldnt worry too much, tilting a motor up and or driving home can do that.
Just check that your primer bulb holds firm with the engine off and tilted down otherwise your carb floats are wrong
 

sumocomputers

Petty Officer 2nd Class
Joined
Feb 23, 2015
Messages
123
I wouldnt worry too much, tilting a motor up and or driving home can do that.
Just check that your primer bulb holds firm with the engine off and tilted down otherwise your carb floats are wrong

Cool. I made sure the floats were adjusted perfectly to spec, so I feel pretty confident about that.

I guess the gaskets are not really meant to totally seal liquids like fuel, but just so air doesn't get sucked in?

I have a new OMC fuel/bulb assembly to install tomorrow, and if it still doesn't get firm, I am going to look at the VRO pump. Probably go with a fuel only pump from MaxRules if needed, since I disabled VRO awhile back. And at $80 it's about $360 cheaper than a new VRO pump, and about $75 cheaper than the VRO rebuild kit.
 

Bosunsmate

Admiral
Joined
Apr 7, 2012
Messages
6,135
Cool. I made sure the floats were adjusted perfectly to spec, so I feel pretty confident about that.

I guess the gaskets are not really meant to totally seal liquids like fuel, but just so air doesn't get sucked in?

I have a new OMC fuel/bulb assembly to install tomorrow, and if it still doesn't get firm, I am going to look at the VRO pump. Probably go with a fuel only pump from MaxRules if needed, since I disabled VRO awhile back. And at $80 it's about $360 cheaper than a new VRO pump, and about $75 cheaper than the VRO rebuild kit.


Yep, air causes lean running so thats very true
id never keep a vro
 
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