Good evening, I have a 203 Yamaha 2 stroke 150hp. It has 125 psi on all 6 cylinders and great spark. It has 3 carbs and only the mussel carb has good vacuum. The other two is almost non existent. If I pull the boot off either of the middle two spark plugs, there is a noticable decrease in power and sound. HOWEVER, if I do the same to the other 4 spark boots....absolutely no difference....
Is it reed valves? Is it a vacuum leak at crankcase gear? I really am out of answers with this! Any help would be awesome!
Is it reed valves? Is it a vacuum leak at crankcase gear? I really am out of answers with this! Any help would be awesome!