I have a 1991 johnson 200-- E200STLEID--- The motor seems to be short on power for some reason. I though that maybe the plugs were fouled so i pulled all 6 plugs out and noticed that 5 of the plugs were covered in burnt oil and were black, but the other plug was very clean looked like new. I put these plugs in at the same time so they have all been in the same amount of time. Any idea what might be the significance of this? and does this give any idea as to way i might be not getting all of the power from the motor?