Inner Prop Hub Gunk

[rammerjammer]

2014 Mercury PROXS
Serial 2B021994

Guys, please pardon my ignorance but I'm new to Mercury. I purchased a used Mercury and immediately started using the cocktail and DFI oil as recommended. I have noticed a thick black tacky residue on the inside of the prop and on the outside of the PVS holes.

I also had Mr. Don Weed perform a 100 hour service on the motor. This residue had shown up before and after the service so I assume there is not a gasket and/or leak because it would've been found during the service.

With that being said, is this tacky residue normal when using the cocktail and DFI oil? My assumption is the prior owner did not use the cocktail and the motor is discharging the build up over the last 2 years?

[Savage]

Do you run the boat at WOT for long periods of time, or do you just putt around graphing mostly?

[rammerjammer]

Run time: 650 - 1499 (88.9 hours), 0 - 649 (44.9 hours), 1500 - 2999 (10.6), 3000 - 5699 (87.7), 5700 + (6.6).

I've put about 4 hours on the motor and have pushed it to see what the capabilities are. (5600 - 6000) from spot to spot.

[SilverFox579]

Run time: 650 - 1499 (88.9 hours), 0 - 649 (44.9 hours), 1500 - 2999 (10.6), 3000 - 5699 (87.7), 5700 + (6.6).

144.4hrs (65% of total engine hours) under 3krpm. Previous owner spent a lot of time putting around graphing or whatever and that's why there's carbon in the prop hub. You'll probably see this clear up if you don't repeat practice of previous owner and make good long runs over 4krpm.

[EuropeanAM]

+1

Try to end each outing with a nice run in the 3500-5000 RPM range (it does help).

[BigSexyPhoenix]

I run Merc DFI oil and Dons cocktail in mine since new and it has the same thing on the inside of the hub. I don't idle much but o don't run balls to the wall everywhere I go either. Usually run at a nice cruising speed around 4000 rooms. I do give it a nice run at the end of the day though

[leonreno]

Is this type of gunk more prevelant with Optimax motors? Seems they would be cleaner but then again maybe the oil doesn't burn away as much in an EFI or carbed motor, not sure. I have a 200 carbed Mercury and I have a 10-15 minute idle(maybe more) back to the ramp through a no wake zone at the ramp I go to. I have never seen build up on my hub and I also rarely go over 5000 rpm usually 4-4500 rpm. I use non-ethanol with the cocktail, though even before using the cocktail I never saw hub gunk.

[EuropeanAM]

More prevalent in Optimax Models, especially where incorrect oil, fuel octane, lack of Quickleen, and/or excessive idling/low RPM are at play.

Items that you can do to reduce carbon buildup in the exhaust/engine:

-Run the correct OCTANE fuel (87 octane in this case).

-Optimax/DFI Oil

-Quickare/Quickleen coctail in EVERY tank

-Verify engine is coming up to temp (thermostats stuck with debris will make it run RICH)

-Have Rails, Injectors, Direct Injectors (professionally validated, cleaned, serviced and adjusted/repaired as necessary) **

** I recommend this at 3yr/300 hour intervals for Optimax models.