Even though I have been using the cocktail on all of my fuel, the previous owner didn't always do as such. I am thinking I may have carbon build up in my Mercury 200 EFI. Regardless if I do or don't have any build up, I want to be sure the engine is performing at its very best. I picked up a can of Power Tune. It says on the can for carburated and EFI engines. It gives instructions on how to use on carburated engines, but not EFI. How do I use this? Remove air box and spray in air intake?