Test the fuel delivery from the accellerator pump. We sell complete ethanol compatable pumps for $12 plus shipping. They have the grade 5 flourostomer seal, garter spring, custom duration and delivery springs and a new retainer.
I would also install one of our high flow Viton tipped needle/seat assemblies at the same time.
We get similiar calls and emails daily, and in almost all those parts have failed or are failing due to the ethanol in the fuel.....Cliff