I have an Echo PE-2000 type E edger that won't prime, will run with starting fluid sprayed down the intake. I can't find an IPB to determine which port is the uptake or return line. The needle valve is functioning properly. Also, it will run fully choked but at a very low RPM. It just isn't getting fuel. When I remove the primer bulb assembly there is only one fuel line connection, is that the input or return line? Thanks. Gerry at gwhfish@comcast.net