Mikuni carbs....tech question

[Rome-Brewah]

I figure someone on here will know this if anyone will.  It's been a while since I was more of a two stroke gearhead.  The sled sat ('84 yammie enticer 340 single carb) for a couple years and I picked it up from my parents house and is running a little rough after fresh gas and plugs, so I pulled the carb to clean it out.  At the bottom of the airbox side of the venturi, there are 3 ports.  The ports are about 0.0160" in diameter and 0.250" deep with a pinhole at the back of the port.  If I remember, these 3 (and if I remember, some mikuni carbs only have 2) ports, usually only one of the ports is actually used anyway and their function is to put slight postive pressure into the fuel bowl to assist the vaccuum to draw the gas up through the jet needle into the venturi.  The left port was open, the middle port was plugged solid and the right port was gunked up.  Cleaned them out along with the rest of the carb jets and ports, but ran out of time to reinstall and try it out.  I was trying to remember what those ports did and see if it could the culprit for the stumbling on mashing the throttle I am experienceing. 

Thanks in advance
RB

[1TIGGER]

Don't those have an accelerator pump on them ? I know some of them do and if yours does that sounds like it could be what the problem is .
Just a guess without actually seeing it .

[Rome-Brewah]

This is the older ('84) butterfly style.  Do the one's these old have an accelerator pump?  Guess I am not sure where I'd find it.  There was 2 electrical wires that I had to disconnect when I pulled the carb out of the machine.  I was not sure what they went to.

RB

[1TIGGER]

If it does have an accelerator pump it will have a cap on the side of the body that will have either three or four screws and a thin gasket under it . Remove the cap and under it will be a diaphram and that's the pump . Sometimes they will look to be in perfect condition but all it takes it a pinhole in them to do what yours is doing .
That's if yours has a pump .
As for the wires ... not sure without seeing it but they are more than likely ground wires but usually they aren't grounded to a fuel source ?

[Rome-Brewah]

I am not sure this carb has a pump then, I don't remember seeing what you are describing about the cap and screws.  If I remember correctly, the wires went to a switch under the idle adjustment.  Yammie had a feature for the mid 80's where if you let go of the thumb throttle, the idle adjustment lever made a contact to a switch and put the sled at automatic idle.  I think this was to eliminate idle creep from over idling.  I just automactically assumed that's what these two wire were for, but I will investigate further when I get home to see if it is indeed for an accelerator pump...but I don't think they are.

RB

[Profishing]

You sure they are even wires? And not oil injection tubes that run to your carb manifold? Makes me wonder though if its Single carbed oh wait the manifold is in the shape of a y right ?. I never seen wires on a older carb on the enticers and i had lots of them. Your problem sounds like a sticky choke plunger problem ,it may not seating correctly but haveing all the richer and leaner air ways and over flow ports clean may be another task ,as you already know. I would pop another simular mikuni carb on that sled check ebay they are not badly priced.
I sure liked those old back pounder sleds way to stiff of a suspension wait no suspension .

GOOD ENGINES AND IF TUNED and tweaked proper THEY CAN LIFT THE FRONT SKIS NO PRBLEM>

I use to blow away newer machines off the line on the ice with my old beater. 

[Rome-Brewah]

 I was checking online for that year.  The wires are for the auto idle switch.  I blew the carb out with cleaner and compressed air and the only real spot I saw build up was in those 3 ports on the airbox side of the venturi.  I talked with another guy here at work who's rebuilt quite a few sleds, I guess the 3 ports help with atomization of the fuel at different RPM ranges...so this could definately be my culprit.

Yeah, we've owned the sled since it was new.  You couldn't get a more perfect ice fishing sled...it's the long track model and had the oil injection too.  For only a 340, it had nutz for its time.  We put a crap load of miles on it over the years with little to no maintenance to it. 

RB