arbCub Cadet 126
New Member
I have a Zama carburetor, Model C1U-S77 ,off a Stihl Ms-210 chainsaw. The inlet needle and seat hold pressure but if you tickle the metering diaphragm to pressurize the metering chamber with the high and low speed needles seated the metering chamber looses pressure . I am not sure if this means there is a problem with the high or low needle not seating , or if there is a problem with the nozzle or idle check valve. Are the check valves located after the high and low speed needles in the fuel flow circut? The carburetor doesn't have a primer. The problem I am having with the saw is that it will start and idle but won't accelerate . I checked the air filter, the ignition , the compression ,the spark arestor screen, the fuel filter, the fuel line, and pressure checked the crankcase, I also checked the metering lever height and the inlet screen. Some times you can get it to accelerate if you play with the throttle trigger. I also tried changing the high and low speed adjustments but it didn't make a difference.