I've got a fairly loud rattling noise coming from my 88 150GT Johnson WITH a jet pump on it. It has the VRO2 upgrade in it (if/like that makes a difference). I don't have a lot of experience with 2 cycle motors so I'm asking first. I listened to each cylinder with a screwdriver stethescope and each sounds a little different than the other with most sounding similar to a reved up sewing machine. The bottom one on the left hand side seems to have more of the rattling sound present than any of the rest but it doesn't seem that the noise really is coming from there. Not very strong compared the racket the rattling noise makes. The only place it seems really loud is on top of the flywheel at the bolt center, like it's coming from the main bearings. I looked for something that might be loose and hitting the flywheel but there isn't anything. The sound pretty much dissapears or maybe is so constant that it appears to go away when the motor is running at speed. What might I look for?