Hey guys just a quick question. I have a 1972 125 johnson. It goes like stink, but rescently when I hit the throttle it seems to stuttor and not reach it's full speed. It will momentarily jerk and really take off but then it will slow down a bit and keep stuttoring until I put the throttle about half way then it's ok. It was running fine about 2 weeks ago at the lake. Could this be from running to rich, carb's, fuel filter? I don't really know where to start looking. thanks alot.