I have a 2002 Yamaha 115 Four Stroke with 38 hours that typically has not been used at slow speeds. Previously I posted a concern about my prop nut/hub being extremely black from carbon and wonder whether the motor was running too rich.<br /><br />Subsequent to that post, I talked to some other 115 owners who indicated that they had no such carbon build up on their prop hubs. A visit to my local Yammy dealer produced no answer as to whether or not such carbon build up was normal, but they did offer to run a computer diagnostic on the motor.<br /><br />My last oil change was done by the dealer at 20 hours. After reading in this forum about some Yamahas "making oil", I checked my oil level and found it about 1.5 inches above the dipstick maximum. Three questions:<br /><br />1. Is this overfill of oil the most likely cause of my carbon build up?<br />2. Would this lead to making oil?<br />3. Could it damage my motor?<br /><br />Any responses would be appreciated. 
