90 HP Yamaha - Ethanol Woes

[RidgeRunner]

What do I need to do? 4-stroke Late Model

Raycor Filter plus the factory filters were all muddled up. Fuel line is getting soft. My buddy may have put off the replacement of the fuel lines too long. Now it won't turn full RPM and the idle has gone south. If it was a Merc I would be pulling the injectors and sending them off.
What do I need to do first? Besides replacing all the fuel lines and filters?