Motor is a 2004. Serial number OT918886. Recently replaced all fuel lines from tank to motor including primer bulb. Now, the lines will not hold fuel at lower RPMs, but it runs perfectly fine at top end. Every time I come off pad, The motor bogs then stalls. I have to pump the primer bulb back up in order to get the motor to start. Does this sound as simple as possibly a fitting that is leaking air? Did I install the wrong size fuel line? (3/8"). Or do I need to start looking at fuel delivery under the cowling?