Hi to all,

Well, after 213 flights with a Saito 125 conversion, it went lean and this after 150 flights or so without a needle tweak which indicated something was amiss with the fuel system. The problem was quickly found to be the muffler pressure line had split and come off the muffler tap. It seemed a reasonably good time during winter to overhaul the entire fuel system.

Found was the muffler tap fitting was about 80% restricted and reamed out. The muffler itself had only a small amount of interior carbon and got wire brushed to quickly clean. Plugging the vent line and blowing into the fill line required a fair amount of lung pressure to produce a reasonable flow through the inline filter out the carb line. The filter was removed, and flow increased with less but still a fair amount of lung pressure needed. Thus the inline filter needed replaced and the likely source of remaining obstruction was the felt clunk, which will also be replaced.

The tank bung was stiff coming out and solidly formed so will need replaced. The pick up line was small Tygon and hardened. There was perhaps a half dozen floating specs of carbon in the remaining fuel in the tank.

The pressure line had not been filtered nor had a crap trap been used. Engine compression continues to feel good. Oil used is Stihl high performance (petroleum based) @ 20:1. Engine powers a 91" Cub.

Fuel lines, including pickup line will be replaced with Sullivan Pro Flex.

My one question is will the Pro Flex handle the heat at the muffler tap or should that be Viton?

Arlyn