Chainsaw hard to start after refueling

 I have a 455 rancher chainsaw model; that is 4-6 years old has cut 4-6 cords of wood a year.
Recently I adjusted the low idle because it would not stay running at idle.
 
This past weekend while out cutting wood. it took considerable effort ( lots of priming and pulling) to restart after running out of gas and refueling.  Once running it works great.
 
My thoughts initially were bad primer bulb as it always has air in it. I took the primer bulb out tonight.  both the one way valves seem to be working and it does not seem to have an air leak anywhere so now I'm not so sure its a primer bulb issue.  I've not noticed an fuel leakage
 
I did try once refueling it before it ran out and it was still hardstarting . Is something going on when I lay it on its side to refuel.
 
Any thoughts? thanks Lee