Gas overflowing into carburetor throat

[tangaroa3]

Hi Folks,

After some reading on the subject I take it that gas overflowing into the throat of the carb is due to the needle valve not seating and shutting off the flow. This could be due to debris and or incorrect float setting. Yes? Anything else to look at?
I'm quite certain all is clean with what I've gone through recently, and I'm fairly certain float setting is correct, but I'll check this again.
Dave Neptuen says 7/32 WITH the gasket. I don't believe I had the gasket in place when I set the floats....and I love the idea of using a 7/32 drill bit to measure.
Anyway, my question is: My motor has a slight down angle to the engine installation. Is it correct to compensate for this down angle when making the float adjustment?
My old Palmer (also with a Zenith carb.) had a wedge shaped flange/spacer between the carburetor flange and intake flange so that the carburetor was level.
I have not read any threads about this so I'm curious as to what the experts say.
Don mentions to err slightly upwards on the adjustment. Is this something I should definitely try given the situation?
Thanks.

[edwardc]

Hi Folks,

After some reading on the subject I take it that gas overflowing into the throat of the carb is due to the needle valve not seating and shutting off the flow. This could be due to debris and or incorrect float setting. Yes? Anything else to look at?

Yes. Check the float body to be sure it isn't partially filled with gas. A few years back, I had gas overflowing incident. The valve & seat were clean and perfect, and static testing with air showed the valve to be sealing. But the partially flooded float didn't have enough buoyancy to generate enough force seal the valve against the fuel pump.

Take the float out and shake it next to your ear to see if you hear any sloshing. You can also balance it on a straightedge to see if the two float halves are equal. A flooded float will balance off-center.

[JOHN COOKSON]

A Couple More

Sometimes it is necessary to dress the seat with a wood dowel. See fuel system FAQ #17.
Also one needs to replace the needle and the seat as a pair. Generally speaking these parts are not interchangeable between manufactures.

TRUE GRIT

[Dave Neptune]

tangaroa3, unless your float is way way to high the float level will not cause any leaks, the seat and needle will and can if not matched and a good fit.

As far as the angle of installation the carbs are a center feed so angle has little influence at all.

Keeping the floats parallel to the carb when adjusting is tricky and necessary for consistent results when tinkering.

Pulling your fuel lines off and on can dislodge and/or cut lil chunks of hose loose that can get caught in the N&S, seen it many times. My preferred method of working on fuel lines is to replace or cut off then get the piece off the fitting to eliminate those pesky lil bits!!!!

Dave Neptune

[67c&ccorv]

Hi Folks,

After some reading on the subject I take it that gas overflowing into the throat of the carb is due to the needle valve not seating and shutting off the flow. This could be due to debris and or incorrect float setting. Yes? Anything else to look at?
I'm quite certain all is clean with what I've gone through recently, and I'm fairly certain float setting is correct, but I'll check this again.
Dave Neptuen says 7/32 WITH the gasket. I don't believe I had the gasket in place when I set the floats....and I love the idea of using a 7/32 drill bit to measure.
Anyway, my question is: My motor has a slight down angle to the engine installation. Is it correct to compensate for this down angle when making the float adjustment?
My old Palmer (also with a Zenith carb.) had a wedge shaped flange/spacer between the carburetor flange and intake flange so that the carburetor was level.
I have not read any threads about this so I'm curious as to what the experts say.
Don mentions to err slightly upwards on the adjustment. Is this something I should definitely try given the situation?
Thanks.

The Zenith updraft carb was designed to provide proper fuel flow regardless of the angle of the carb/engine...that's why Universal chose them in the A4 application.

As long as your float height is set properly then you should be alright no matter the angle your engine/boat is on.

[tangaroa3]

Thanks everyone for the excellent advice. Ken at Moyer is sending me a new float just in case this one is compromised on some way, a new needle and seat and a couple of fresh gaskets. We'll give it another go.
Before connecting the fuel line to the carb I always put it in a clean jar and run the electric fuel pump for a couple of seconds. Firstly to make sure gas is being pulled through OK, and secondly to push out any little bits that may be there. I have a Dahl primary filter (like a RACOR) and an inline secondary. Both new...and I always like to run some gas through these too before connecting to the carb.
Regarding the down angle of the installation. I had read that the angle didn't matter with running these engines, but I thought it curious that my old Palmer had that wedge between the carb and intake to level the carb...also a Zenith...so was interested what the A4 folks thought about it.
I'll keep you all posted.