Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

[Alter Bootsmann]

Hi, I have a 1989 Johnson V4 110. I am new to outboards always had Mercruiser. My question is why when I trailer my motor, does fuel and oil mix come out of the engine? Is this normal? It drains into the drain well of the boat and out into the water or the road.
When I took the cover off,I could see fuel mix leaking around the "Air Silencer" area (at least thats what the parts manual calls the cover that goes over your carberator intakes).
Does the gasket on the "Air Silencer" normally keep this fuel from coming out? I am assuming this fuel mix is falling out of my carberators or the intake area? If so then maybe a new gasket might help?
I just had an impeller installed by the mechanic. Did he have to remove these parts to get to the shift shaft release? If so, that could be what started the leaking?
Any help is greatly appreciated!
AB

 

[Auxlarry]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

The mechanic did not have to take the airbox cover off to get to the shift rod disconnect but he may have, who knows unless you ask him.
The airbox cover should have a cork gasket on it and all of the bolts should be in place to keep the cover from leaking. If the gasket is oil soaked or just doesn't look right it should be replaced. I replace mine every time I rebuild/clean the carbs.
Your original question is, Yes, the carbs will leak back when the engine is in the full tilted position and the extra fuel/oil mix should be collected in the airbox. Once the engine is lowered to the run position the excess fuel is sucked back into the engine through the lower hose/check assembly.

 

[archcycle]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Some leakage will just happen when the bowls are full and then the boat sits up while it's really hot out and gasses expand, but if you're having this problem right off the water then you probably need to buy a set of rebuild kits for the carbs including the floats and needle seats. I've read a lot of people advising to run the bowls empty on the way to the dock but that never sounds good to me, at least if you're pre-mix like mine.

 

[Alter Bootsmann]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Thank you! I will order a new gasket asap. Do you happen tp know the torque specs on those bolts? Thanks again.
AB

 

[archcycle]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

I've never torqued the carb bolts and haven't had issues. Good and hand tight not over tightened and you ought to be just fine.

 

[Auxlarry]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

I'm sure there is a torque soec listed in the manual but I agree with archcycle. I usually use a 1/4" ratchet and just snug the bolts down. Don't tighten too much or you will squeeze the gasket out.

 

[Alter Bootsmann]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Thanks again fellows! I will let you know if it works.
AB

 

[Alter Bootsmann]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Just getting back to this thread. No, installing the new gasket did not help at all. As others have already told me, "it is the nature of the beast." So I just hose down the engine / swash drain area after every trip.

 

[jonesg]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Some intake silencers have a drain tube that directs the fuel to the block or manifold.
Check there isn't a loose hose or an unoccupied nipple on the lower airbox.

 

[archcycle]

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Re: Fuel leaking out of "Air silencer" when engine trailered. Is this normal?

Just getting back to this thread. No, installing the new gasket did not help at all. As others have already told me, "it is the nature of the beast." So I just hose down the engine / swash drain area after every trip.

It is not the nature of the beast. It's a specific symptom of a specific problem. You've got stuck carb floats. Pull the silencer off and pump the primer bulb and I bet you get a lot of fuel. Find out which ones are leaking and at very least rebuild those. Preferably do all 4. It is extremely easy you'll be surprised.

It's dangerous to have that leak. You have fuel, air, and enough enclosure inside the cowling to give compression. What you have under your cowling is quite literally a bomb waiting for a stray spark. That gasket is a just-in-case to prevent your bomb scenario in the event of a tiny bit of leakage. It can't keep up with your leak.