My mecury EFI started last fall to loose power after running a while you could run half thottle fine but not full. Now it will not even get my 18 ft aluminum boat on plane it idles fine give it gas and it just falls and stubbles. Was in shop for 8 weeks machanic says he don't know. It gives no alarms he said his computer shows nothing. Does anybody have any idea or do I need a different machanic. Thanks in advance for any ideas, James
