I have a 2006 115hp 2 stroke 4 cylinder mercury. It starts great, idles fine, runs good at lower rpm. It will not run as fast as it use to about 5-6 miles per hour less. It seems to bog down if I floor it and runs funny at top speed input. Carbs are clean. Feeder hose from tank to engine replaced and the bulb pump. New plugs put in. This helped a little but still not right. I only run 100% gas. Any suggestions from experience?