carb adj. 49cc 2t

[ravenrock67]

I am a noob with automotive exp. so please forgive my goofs. I have a scooter given to me that is giving me issues. The carb was replaced by previous owner, it is a mikuni style. At first gas poured out of a tube at the bottom of the float bowl. This I assumed was an overflow/slosh vent tube. The bike ran like crap but it ran. after the tear down of the carb I found that the owner had routed fuel to the vacuum port for the petcock, and the petcock to the fuel inlet. after assembly it starts sluggish, then starts, idles high and when give it gas it reves up, let off the throttle, It stays higjh , 3-4k RPM, then it idles down eventually but then it dies. the question I am asking for is this, I see a needle adj. screw, Is there a good way to adjust this needle. I assume this is an idle adj. screw. what is the best method for setting it. If this were a HOLLEY carb i would set it at 4 turns and after engine running back it in until 2 1/2 turns out. any help would be great

[edfr]

The tube at the bottom of the Bowl is your Drain Hose. Some Carbs have a screw right next to it to drain the bowl, others have the drain screw on the end of the Hose.

You should have at least two adjustments one is for IDLE, and one for Air/fuel mixture
Does your carb throttle cable go into the top of the carb if so you have what they call a SLider type carb. If the throttle cable is on the right side on a bracket it is a CV type carb.

If A Slider type there is a big screw on the Left Side, that controls your IDLE it move the Slide inside up and Down. The other screw is your Air/Fuel mixture turn that in and count the number of turns it take until it stops. Then turn it out 2 1/2 turns and see how it starts up.
If it starts up with to HIgh of an IDLE turn the Big screw Counter Clockwise to Lower the Idle.

Once it Warms up then you can Adjust the Air/Fuel Mixture better.
Lefty