I had an issue that suggested I needed to clean the carburetor on my 2005 3 liter Mercruiser TKS engine. It was flooding out when I returned the throttle from 4500 rpm down to idle (no load on engine, running in yard with muffs). My carb is 866140 (with fuel enrichment module as opposed to electric choke). I cleaned the carb and set the idle mixture screw a full 2 turns out, knowing that it would require more adjustment once I get the boat on the water. I started the engine (with the muffs). It started in idle throttle position and the rpm increased up to 1800 and stayed at that point until engine temp reached 175 at which time it slowly reduced eventually stabilizing at 1200rpm. I could increase throttle up to around 4500 rpm and then pull throttle back to idle without the engine flooding out so I believe I corrected the initial problem. My question: where should the rpm be at idle (remembering that there is no load on the engine)? will closing on the idle mixture screw reduce the rpm during idle? or should I adjust the idle adjustment screw to drop the rpm?
