I have a Volvo Penta 220hp, 5.0 GL (Carb. engine) on a 2004 20' Ebbtide bowrider, bought brand new 13 months ago.<br /><br />Just yesterday, I noticed that it was idling a bit high...900 RPMs. Also, the engine was vibrating, something I haven't noticed before.<br /><br />When I drop into...