Hi, am looking for ideas what might be wrong with my older Echo Brushcutter with Walbro WA175 carb (no primer bulb).
Last year it was very difficult to start on the cord, but it did eventually and ran "OK" if not a little flat at trying to pick up revs. Once it got going at full revs it went great. Spark is okay, new fuel filter last year, very little use since.
This year - will not start at all on the pull cord without putting some fuel into the carb after taking off the air filter. Still has decent spark. It then runs, then dies. Starts again on the pull (set at full throttle) without adding any more fuel to the carb, but dies again. Adjusting the H/L screws has no effect.
My thoughts were perhaps a split fuel pipe, but I have replaced this and it hasn't helped. The fuel pump on the bottom of the carb has fuel in it, but it doesn't seem to be getting through to the cylinder. I have blasted out the holes on the carb with air, and replaced the gaskets and diaphragms on the carb, checked the H/L pins etc.
Could it be the gasket (paper type) on the rear of the carb that goes to the cylinder could be the problem as this is the only thing I haven't touched yet?? It looks a little ropey (possibly original), but seems a reasonably good seal, but to my untrained eye I cant see why this would affect it the way it does?