Don't run it long or hard if you think it's running lean, as that's a quick way to overheat pistons, and if you're running premix you're also starving the motor for oil! I'd suggest you duplicate BRP's fuel system test, i.e., in the line between the filter and engine, install a section of clear vinyl tubing with a vacuum gage tee'd into it. When you run the motor, look for bubbles in the clear line from an air leak, and monitor the vacuum gage @ WOT to see how much restriction you have between tank and engine. The limit they use is 5"Hg, but lower is better. Each 90 degree elbow in the system is typically worth about 0.5" Hg pressure loss, but I've also heard of 3/8" elbows that weren't drilled out properly, so they were only 1/4" inside, so that would also cause significant restriction. If you get a high reading indicating a blockage in the pickup tube try blowing back thru the line with a high pressure air hose. Also make sure tank vent isn't plugged up with wasp nests, etc. Maybe try running off a portable tank to confirm problem is in fuel tank.
|