HI,<br />I HAVE 1989 JOHNSON GT 150 IT IDLES LOW AT THE LAKE AND HIGH AT HOME. IT ALSO WILL NOT RUN AS FAST AS IT DID 2 OR 3 MONTHS AGO. I HAVE PUT NEW PLUG IN AND REBUILT CARBS. SOMEONE SAID TIMING MAYBE OFF. MY MANUAL SAY TO SET IT AT 28 DEG. AT 5000 RPMS. IS THIS CORRECT? THANKS FOR ANY HELP!