Black gunk inside prop.

[DDNichols7]

Notice today that there was black gunk inside my prop. Unsure how long its been there. What is this? Unburned oil? Is this normal? Good or bad and what to do to fix it? I have a yamaha vmax 225 hpdi. Thanks.

 

[minner]

Most likely carbon. I'd run a little seafoam through it if it were me.

 

[catch 1]

Mercury recommends Quickclean to prevent carbon build up. The directions read to add 1 ounce for every 6 gallons. I use it every time I fill up. Acadamy Sports has it.

 

[Bumble Bee Kid]

It's just exhuast soot and carbon no biggie every motor does it. Yamaha recommends Ring Free for there motors. It will keep it at a minimum but the inside of your prop is always gonna be black as long as your using it.

 

[lucky rapala]

all will do it and if u keep it at the same rpm that will do it more u need to gun it and that will help it some but they will all do it

 

[Todd 450r]

Defintely run Ring Free in the HPDI. 1 oz per 10 gallons. Carbon build-up and ethanol are the 2 major factors that can blow these direct inject motors. If you haven't been using ring free, there is a shock process that can be done to remove any existing build-up that you have and then run the recommended 1 oz per for the remaining time.

You will have soot/carbon in the exhaust regardless, but I can't stress enough to keep this carbon build-up to a minimum. When your motor is running right, there shouldn't be much on your prop, definitely not enough to build up and clump up. Just a thin layer of black soot.