The relationship between mixture screws and idle speed screw needs to be proper. If the mixture screws are in too far, you can make the carb idle on the main metering circuit - though not very nicely. As Cloaked said, start with the idle mixture screws 1 1/2 turns out and get you idle speed set properly.
If the diaphragm on your power valve (and it should be 2.5) is ruptured, it will run full rich and give you black smoke coming out the exhaust. The only true way to test it is to remove it and hold the outer diameter of it while trying to gently twist the pointy end. If it turns freely it is bad. By turning your mixture screws in all the way, the engine can still run if there is a significant base gasket leak.
ONE TIME TANDEM AXLE PACKAGE DEAL
ONE PACKAGE AVAILABLE AT THIS PRICE
5 14X5.5 T06 WHEELS W/GUNMETAL INLAY
5 ST215/75R14 KENDA LOADSTAR KR03 RADIALS
STAINLESS CENTER CAPS, LIFETIME CHROME LUGS
MOUNTED, BALANCED & READY TO INSTALL
SNOWMOBILE TRAILER TIRES & WHEELS
PM or email me for package pricing.
CARBURETOR REBUILDING - $125 + PARTS
LED lights, Chrome & Powder Coated Lugs