carb dripping gas out of the venturi.

krisnowicki · Jan 15, 2011

I have rebuilt this carb all new needle, seat and float. I have adjusted the float, and adjusted the float, and adjusted the float. When there is no pressure coming from the fuel pump the carb does not drip. But when the pump is on it drips about 1-2 drips a second so idle is not possible. These are simple carbs what else would cause this drip?

So close but so far....

Don S · Jan 15, 2011

Re: carb dripping gas out of the venturi.

You missed a couple of necessary items in your post, and signature. What carb, and what year. SN would be handy too for some.

krisnowicki · Jan 15, 2011

Re: carb dripping gas out of the venturi.

2006 bravo 250 hp 5.7 with a 2bbl mercarb ( one mixture screw)

fat fanny · Jan 15, 2011

Re: carb dripping gas out of the venturi.

I had that same issue for about 20 seconds after my rebuild on my Mercarb the summer before last and after a few light taps on the carb body with a screw driver handle never happened again but yours could possibly be needle and or seat issue, debre that wasn't flushed out during cleanning, or yet another float adjustment. Was it a merc rebuild kit? or after market I bought aftermarket and used merc manual instructions instead of aftermarket float measurements were slightly diffeerent. Good Luck!!!!!!!!!!

Don S · Jan 15, 2011

Re: carb dripping gas out of the venturi.

Is this a TKS carb?

krisnowicki · Jan 15, 2011

Re: carb dripping gas out of the venturi.

this is not a tks

CobiaXL · Jan 16, 2011

Re: carb dripping gas out of the venturi.

either float or need and seats would cause it..Take float out and stick in glass of water to make sure its not leaking..Look thru needle and seat with flash light.If you see light thru it when closed then u know its defective.

krisnowicki · Jan 16, 2011

Re: carb dripping gas out of the venturi.

Needle and seat are new. When I have the carb out I flip it over and blow in to it. No air get through. The float, floats. I put it in a tank of gas and it does not take on water and it weighs the right weight. I am thinking my new lp fuel pump merc part # 861155A 3 is putting out too much pressure

telstar1 · Jan 16, 2011

Re: carb dripping gas out of the venturi.

Have you tried overadjusting the float to see if that stops the drip ie bend it down too far so that it floats with very little fuel in bowl. If that works you know needle seat is ok,bend it up a bit till you get enough fuel in bowl to run but not leak etc etc. Not exactly textbook techniques but this has worked for me in the past. You will by this process likely find where the problem really lies and "get er going".You may just be doing the float level adj. wrong somehow.
I have a 2002 5.0 with 2 bbl likely the same carb. I havent owned it long but did notice the other day that it "drips"at idle although less than yours. It idles fine.I will be trying the technique outlined above but so far it isnt high enough on my priority list. Wouldnt be the first time Ive seen a prroblem cured by running a lower fuel level in bowl than spec calls for..

oldsh_t · Jan 16, 2011

Re: carb dripping gas out of the venturi.

Things to check:

>When you replace the needle and seat, did you install the gasket to? (Need the gasket)
>When you are adjusting float levels, are you taking measurements with the air horn gasket in place? (You Need this gasket in place)
>When you are adjusting float levels, are you using the right mark on the float itself.

>Which needle and seat are you using? There are 2 and each have a different setting

>On the float drop you have to use the same mark with gasket in place as before.

krisnowicki · Jan 16, 2011

Re: carb dripping gas out of the venturi.

pump puts out 10 psi

Don S · Jan 16, 2011

Re: carb dripping gas out of the venturi.

3-7 psi is where it should be. Has the pump been replaced with perhaps the wrong pump?

krisnowicki · Jan 16, 2011

Re: carb dripping gas out of the venturi.

pump was brand new from iboats.com

it is the right part I got it all together and running

CobiaXL · Jan 17, 2011

Re: carb dripping gas out of the venturi.

10psi to much without regulator....I've also seen needle and seats bad out of box,check with flashlight to make sure it seats tight.

carb dripping gas out of the venturi.

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