Fuel seeping past needle / seat in carb inlet throat

[Corrugated]

Hello All,

Further to my other post on my 2004 running / fueling issues. I noticed the other day, when the engine was running, after I did a Shotgun clean of the 4 carbs, that fuel was seeping past the needle / seats inside the carb inlet throats, on all 4 carbs. I don't recall noticing this in the past and not sure if this is a normal operating function? When I pulled each diaphragm and needle to perform the carb. Shotgun clean, the needles and seats did not look dirty or worn, I just wiped them down with a clean paper towel and reinstalled them. Wondering if this is not normal, is the fuel coming from overflowed float bowls, then going past the needle / seats, then making its way into the combustion chambers, hence the high running rpm and backfiring that I was experiencing..?

Thanks again in advance!

 

[Fire-medic]

Hello All,

Further to my other post on my 2004 running / fueling issues. I noticed the other day, when the engine was running, after I did a Shotgun clean of the 4 carbs, that fuel was seeping past the needle / seats inside the carb inlet throats, on all 4 carbs. I don't recall noticing this in the past and not sure if this is a normal operating function? When I pulled each diaphragm and needle to perform the carb. Shotgun clean, the needles and seats did not look dirty or worn, I just wiped them down with a clean paper towel and reinstalled them. Wondering if this is not normal, is the fuel coming from overflowed float bowls, then going past the needle / seats, then making its way into the combustion chambers, hence the high running rpm and backfiring that I was experiencing..?

Thanks again in advance!

View attachment 92595

Yes normal operating function. The slide needle is working with the emulsion tube to pull fuel out of the float bowl. This is the Venturi effect that a constant velocity carburetor has.

 

[Corrugated]

Excellent, thanks for confirming that. Now I can diagnose / fix the other issues I believe that are causing the troubles.