I have a 40 merc 4 cyl that is running poorly on aceleration and top end. I did the normal checks and then sum. 135 compression on all 4 clean blue spark on spark tester 1/2 gap replaced entire fule system tank hoses ball rebuilt the carbs set the float level all new hoses on the motor reseculation and all fule pump rebuild. The oil injection has been removed including the tank. pre mix now. The boat will get on plane but only with the cowling off and even the at wot it sounds rich and if I lift of the throttle to 3/4 or so it cleans up and sound good but still not 100%. The spark plugs look to clean to me for a 2 stroke. I have been working on 2 and 4 strokes for 18 years this ones got me stumped. dynamite is the next tool That comes to mind. please help if u can. Thanks
