Hole in Carb ???

[Big Jay]

Model FD-12, 18hp Johnson....
This hole is leaking a lot of fuel when my engine is in the upright tilted position.

(red circle at tip of screwdriver)


It looks factory made... but I'm not sure, any ideas on what it is? Is it supposed to have a lead shot or something? It's not very big in diameter

Thanks in advance folks, this forum is a wealth of information worth it's weight in gold

 

[Chinewalker]

Re: Hole in Carb ???

It's an air vent - it is supposed to be there. If your carb is leaking from the hole, then it is likely there is an issue with the float or float needle...

 

[Big Jay]

Re: Hole in Carb ???

Thank you for the response ChineWalker...
Ok... when i put a carb kit in it last fall it didn't come with a float, I'll order one right away. I have the current one bent a little shy of level to the housing now to prevent overflow issues, but it must be logged then.
I'll post my findings!

 

[Joe Reeves]

Re: Hole in Carb ???

1958 18hp Johnson FD-12

I'm in agreement with Chinewalker pertaining to the float and/or the float needle valve but there could also be another reason.

The vent leads to the float chamber.... If the vent passageway is somehow clogged at some point between the exterior vent hole and the float chamber... any incoming fuel will flow out of the carburetor. A rare but existing problem that will drive a person nuts if not aware of the possibility.

However...... I don't recognize the top portion of the carburetor picture as a 1958 18hp carburetor nor the hole pictured. The vent hole that normally leads to the float chamber would be on the front right (port) portion of the carburetor approximately halfway down the throat curvature.

(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.

 

[Big Jay]

Re: Hole in Carb ???

Oh crap!! lol

I hope it's the right carb, there are some mounting screw holes for something on the starboard (same side as said hole) side that I'm not sure of tho...

Here's some more pics in hopes that you can tell me if it's the wrong one (Good Lord)

 

[Joe Reeves]

Re: Hole in Carb ???

Disregard the portion of my previous post pertaining to the carburetor being the wrong one for that engine, my apologies. I had two parts manuals hooked together and flipped to the carburetor page on the wrong manual. That is the correct carburetor according to the proper parts manual.

However, as I mentioned.... after installing the new float & float needle valve, if the carburetor still forces fuel out the vent... check for something clogging the vent passageway leading to the float chamber.