Yamaha 115 Four Stroke Question

[alumacomp]

I have a 2002 Yamaha 115 four stroke with 38 hours on it. It is never used at low speeds. I am experiencing a lot of carbon build up on the prop hub (the nut is black). The motor seems to run OK but on one occassion I did notice a cloud of smoke upon start-up after a brief shut down.<br /><br />Is this normal or is the motor running too rich? Could my use of a fuel stabilizer be contributing to the carbonizing?

 

[nanoa]

Re: Yamaha 115 Four Stroke Question

I have a 2005 f115 I have the same build up which i believe is normal one out of five starts i get a little smoke too

 

[bigbrownbuku]

Re: Yamaha 115 Four Stroke Question

the smoke could have been from the engine being in a negative trim position. upon shutdown trim the engine to the edge of the trim travel to help prevent any oil bypassing the rings while the engine sits.

 

[bossee]

Re: Yamaha 115 Four Stroke Question

Hi,<br />I have a F115 2003 and my prop nut and washer has always been mor os less "black" from exhausts. I consider it normal. I use 95 octane unleaded fuel (basically the only available in my country).

 

[rodbolt]

Re: Yamaha 115 Four Stroke Question

its carbon. its what happens when ya burn a hydrocarbon. if ya dont belive it rub your fingers inside the tailpipe on your car and see if its black. what BenC says on the start up smoke.