Carbs are leaking... Why?

[Hacker]

I have a problem where my carbs are leaking oil all over the lower cowel whenever I take the boat out. Why would this be happening?
I rebuilt the carbs and it still happens (new front intake gasket leaks as well). This is on a 1979 V4 140.

would it be the float bowl overflowing into the carb? Blowback from the motor? The plugs look like the motor runs rich even though I have 50:1 with premium oil. Please help. Thanks.

 

[Joe Reeves]

Re: Carbs are leaking... Why?

When you rebuilt the carbs, hopefully you installed new float needle valve assemblies. If so, I would assume that the float levels are set incorrectly.

(Carburetor Float Setting)
(J. Reeves)

With the carburetor body held upside down, the float being viewed from the side, adjust the float so that the free end of the float (the end opposite the hinge pin) is ever so slightly higher (just ever so slightly off level) than the other end. And when viewed from the end, make sure it is not cocked.

 

[tashasdaddy]

Re: Carbs are leaking... Why?

http://forums.iboats.com/showthread.php?t=244013

 

[Hacker]

Re: Carbs are leaking... Why?

Thanks for the responses. I followed those instructions when I first did the rebuild. I just took them off again and did the blow through test and it was correct... air passed when normal... did not pass when upside down.
When i removed the old float needle, the float was not level. I leveled it... it leaked, so I changed it back to previous and it still leaked.
When I took it off this time, I noticed that a main jet was loose and may be the reason for the leak... too much fuel passing.
Is that a correct assumption? I hope to test tomorrow.

 

[emdsapmgr]

Re: Carbs are leaking... Why?

My recently-overhauled 79 has the same problem. If you tilt the engine for storage, or when used in shallow water, they seem to leak fuel. I don't have that problem with later crossflow carbs. You have a new airbox gasket between the airbox halves-good move. Make sure the airbox hose is connected from the nipple at the airbox bottom to the nipple on the front, bottom of the crankcase. It will help. Consider replacing the fuel hoses under the cowling. Original hoses were not made for use with ethanol fuels. They will degrade over time and can leak. If yours are original, replace them. Most of them are specially heat formed and have specific part numbers. I'd use the re-useable Bombardier snap-clamps to hold the hoses in place.