I'm new here. I bought a 1993 20' Osprey w/a 150 Yamaha a few months ago. The enigine was sold as a complete rebuild and only had 8 hours. It now has 22 hours and every hour from 10 to the present has been a complete NIGHTMARE!!! The compression is perfect. I have had the carbs adjusted and it ran great for 45min, but once I anchor and fish then pull anchor and head to the ramp the engine will just crank but will not fire. Once it does fire off it has a miss sometimes, sometime not. I'm now having the carbs rebuilt b/c I was told and shown the dirt in the carbs. The engine will not stay running below 1000 rpm. I have had just about enough with motor. I guess I'm asking if a carb rebuild will fix my problem? I know it can't hurt and if the the jets are blocked it will misfire but what else can cause this problem? The spark plugs were replaced after the break in period and the double oil. I also changed the prop b/c the pitch was wrong and it was causing the engine to load up and wasn't turning the engine fast enough.