Accelerator pump

Hello all. My number two carb always runs rich even though I give it an extra half turn of air compared to the other three. I was wondering if the proximity of the accelerator pump to number two causes number two to be over fed by the accel pump.
Does anyone on this forum have similar issues and does anyone here ever set the needle on two at a leaner setting than the other three carbs to try and compensate for the position of the pump. I have all of the needles set in the number 3 slot right now and I was thinking about setting number two by 1/2 -1 slots leaner.
thoughts,
Joe

The pump is designed to provide a small squirt of gas when you crack the throttle.  It is likely not your problem.  I would look for other issues.  Choke plunger leaking a bit?  Float valve set a bit high?  

I agree that if the pump is working correctly it should not be causing the issue you have.  But it might be helpful to learn which set of carbs you have, as there are some differences between how the pumps and the vacuum port for the petcock locations are different between them.

Thanks for your insight, I will check the float level and choke plunger.  If the choke plunger is leaking, would that create a rich or lean condition?
Joe

Thanks for your input. All I know about the type of carbs is what the manual tells me; Mikuni VM 24SS.

I have not replaced the choke plungers and suspect they are original. I will make that my next project. THANKS!
Joe

OK, on the vm24ss carbs the location of the vacuum port for the petcock on on carb #2 while the vm26 or vm28 carbs have the port on carb #3. I am not saying this is the issue but if the diaphragm in the petcock has a tear then fuel can be pulled up into carb #2 on the vm24ss carbs which would make it richer.

Thanks again, the petcock is brand new and does not leak at all with the fuel supply line to the engine removed in either the run or reserve positions.

A leaking choke plunger will make your mixture richer.

I pulled the carbs and cleaned up the starter plungers and replaced all of the o-rings. That made a big difference and the low end is much improved. Not perfect yet, but we are definitely moving in the right direction. Thanks to all for your input.
Joe