Carbon removal recommended by Mercury?

[hooken203]

2016 300XS SER# 1E 053049
I bought a bore scope to check my engine for a possible turned sleeve. None of them are. But while looking around in there I notice what I feel is more carbon on top of the piston than I think should be there. Is there a recommended way to remove this? I have used a couple different ways to do this on the Y brand but not sure on the Optimax. I am running DFI oil and Dons cocktail. Am I mixing the cocktail correctly? I use 9 oz Premium Plus 2oz Quickleen 2oz Quickare per 10 gallons.

[EuropeanAM]

BEST thing you can do is to continue what you're doing, and try to ensure you're making a nice 10+ minute run in the 3500-4800 RPM range near the end of each outing.

If you target the RPM range where the engine get's it's best fuel economy, that's ALSO where it runs the "cleanest". Great range for helping to keep carbon levels low.

An annual decarb is also acceptable, though your DFI engine requires different methods than other 2-strokes. Power-tune, installed in the plug openings with a HOT engine, tilted up, and left overnight is probably the best method. Do this right before you plan to replace the plugs, as it will likely be necessary (after it's been run to clear out the Power Tune).

[bass.man65]

Lose the DFI oil and you will lose the carbon.

[06 SB]

I run DFI oil since it came out. I also use 87 with 10% Ethanol and Don’s cocktail. No issues with carbon...ever. I probaly have close to 2000 hours on DFI motors including my first one in 1999.

I properly maintain them. Warm them up, run them hard, cool them down...repeat.

[TritonTRXV8]

I run DFI oil since it came out. I also use 87 with 10% Ethanol and Don’s cocktail. No issues with carbon...ever. I probaly have close to 2000 hours on DFI motors including my first one in 1999.

I properly maintain them. Warm them up, run them hard, cool them down...repeat.

Same here also zero issues for me either been running this engine 7 years now.

[Gamblinman]

Make sure you are using the recommended octane rated gasoline. If you purchase your gas from one location, you might try a different location for awhile.

[hooken203]

I buy fuel at three different stations and they are all high traffic stations. 91 octane min as recommended. It’s not a problem yet. It just surprised me how much is on top of the pistons when I thought I was doing everything to avoid it.

[hstechfl]

Optimax motors run dirty- especially if you idle and troll. Not as much of a problem with bass boats, but more so when center consoles that go offshore (my case). I have to pass through a couple miles of no wake areas and my boat is not big enough where I can open it up in anything higher that 2 ft seas.. so I get a lot of carbon and dirty plugs.

Like Don said, make a long run (if possible) at the end of your outing. This should help keep carbon down and the cleaner you are running should break down the existing carbon. Your motor is pretty new (and under warranty I'm guessing) so I would stick to the manufacturer's recommendations..

[SilverFox579]

Same here also zero issues for me either been running this engine 7 years now.

+3. Top-tier ethanol fuel (have no choice) from same station, recommended cocktail, and 9yrs with no issues. Then again, I make long runs (30 - 45mins) between 3500 - 4400rpm and never troll or idle with my Optimax, that's what my 8hp kicker is for.

[EuropeanAM]

Lose the DFI oil and you will lose the carbon.

Yeah... I guess so, if you don't use oil. And if I stop breathing, my back will quit hurting.

[Gamblinman]

I would increase the amount of Quikclean temporarily and see if that will clear it up.

[Nova Kaw 650]

BEST thing you can do is to continue what you're doing, and try to ensure you're making a nice 10+ minute run in the 3500-4800 RPM range near the end of each outing.

If you target the RPM range where the engine get's it's best fuel economy, that's ALSO where it runs the "cleanest". Great range for helping to keep carbon levels low.

An annual decarb is also acceptable, though your DFI engine requires different methods than other 2-strokes. Power-tune, installed in the plug openings with a HOT engine, tilted up, and left overnight is probably the best method. Do this right before you plan to replace the plugs, as it will likely be necessary (after it's been run to clear out the Power Tune).

I might have to run a heavy dose of Quickleen through my motor in the spring.
I run the cocktail, non-ethanol gas of the correct octane, DFI oil and run it hard when I can, and no idling/mapping/side imaging, etc. The new midsection/tuner (a long story) with about 20 hours had very substantial carbon buildup inside when I had to pull the lower unit off again (another long story, lol). When I winterized it this year, and ran the Mercury recommended cocktail from the VST to the motor, there was a bunch of loose chunks of soft carbon on the plugs when I pulled them out.

[kllr bee]

Run your 300XS over 5000 rpm's all the time like I do and you won't have any carbon buildup.
Richard

[Savage]

Run your 300XS over 5000 rpm's all the time like I do and you won't have any carbon buildup.
Richard

Yep that's what I do.......

[fishnfireman]

Run your 300XS over 5000 rpm's all the time like I do and you won't have any carbon buildup.
Richard

[hooken203]

5000 RPM everywhere I go. Not an option but it gets its miles of WOT high RPM operation.

[kercha83]

I'm starting to think that I'm waisting a whole bunch of money on quickleen if does nothing to reduce carbon buildups running below 4000k rpm (which I do 90 percent of the time).

[fishnfireman]

I'm starting to think that I'm waisting a whole bunch of money on quickleen if does nothing to reduce carbon buildups running below 4000k rpm (which I do 90 percent of the time).

where did you hear that ?

[fishnfireman]

5000 RPM everywhere I go. Not an option but it gets its miles of WOT high RPM operation.

I do the same -- plenty of time spent graphing and no wake zones but also try to air it out when conditions permit. Have used the cocktail in my last two motors.. But have not used a bore scope to check for carbon.
With that said I have a prop that will run an even 70 mph at 4800 rpm-- that's where I do most of my cruising .

[EuropeanAM]

If you're doing everything you're supposed to- and you're fining big loose chunks of carbon in the exhaust, there is a problem that you're not aware of. Often revealed in an Air/Fuel Pressure Test (and pressure leakdown test).