RE: OS91FX With Macs Tuned Pipe need help
Not sure if this will help, but I have a .46 with a Macs pipe. I put the pressure nipple right where the pipe reaches the thickest part of the pipe. The pressure line is indeed quite long. Every time I start the engine, as I first run it up, it acts really really rich, like the motor is loaded up. What I do is pinch the fuel line to let the engine lean out. Once I hear the rpms pick up, I let go of the line, and its fine after that.
My guess is that I have the carb set quite rich to deal with the lesser pressure, but once it picks up, it runs great.