Diagnosing old plugs (2013 200HP Optimax Pro XS serial #1B965288)

[basshole51]

As per the sticky thread on winterization I pulled my spark plugs on my motor to put 5ML of oil in each cylinder...I replaced the spark plugs as I plan to put new plugs in the motor in the spring (boat will be sitting in heated storage for next 4 plus months)....the plugs I pulled out are concerning me as they seem extra dirty.

Some background information in the motor - purchased in March 2019 and had a Mercury factory replacement powerhead installed with 7 hours on the new powerhead when I got boat....that new powerhead now has about 35 hours on it and the bill from Marina that previous owner gave me states injectors/fuel system were cleaned and flowed when powerhead was replaced. I would've have assumed the plugs would be changed when a new powerhead was installed but these look very old to me. Previous owner ran 93 octane and no fuel stabilizers....I run 89 octane or 91 when as that is all that is available as Ethonal free..I also run Don's cocktail in every tank (minus the 150:1 oil mix). I did change fuel filter when I purchased the boat along with a new alternator belt and both were in bad shape which I thought was odd for a new powerhead (motor has 320 hours on it total).

I would like to hear some thoughts from people more knowledgeable than me on how these plugs look....or am I being nitpicky and should just replace?

[basshole51]

#1.jpg cylinder #1

#2.jpg cylinder #2

#3.jpg cylinder #3

#4.jpgcylinder #4

#5.jpg cylinder #5

#6.jpg cylinder #6

[Fishysam]

Run 87 octane even with ethanol over 91, describing how you run your motor rpm wise would help too. If you idle a bunch or if you run it 4000-4500 rpm for the last 5 minutes of use has been recommended to help clean it up

[basshole51]

I do not do an excessive amount of idling and every time out I take my boat up to at least 5500 RPM once or more....I refuse to put ethanol gas into any powersports equipment.

[digthemup]

I refuse to put ethanol gas into any powersports equipment.

Especially since there is '0' need to put any ethanol in any fuel, apart from politicians making bad policies due to large donations taken from lobbyists.

[Dan21XRS]

It's been discussed a million times... These outboards were specifically designed to run on fuels up to and including 10% ethanol. Higher octanes burn at a lower temps which can cause your spark plug to foul... Dan

[basshole51]

It's been discussed a million times... These outboards were specifically designed to run on fuels up to and including 10% ethanol. Higher octanes burn at a lower temps which can cause your spark plug to foul... Dan

thats fine and dandy but 89 and even 91 are hardly higher octane than 87...Ethanol gas doesn't go into anything I own besides my car....I have seen it ruin too many things "designed to run it" and Mercurys stance on ethanol is that it is BAD...I also don't want any ethanol sitting in my tank no matter what kind of "stabilizer" is added to combat its inherent trait of separating and creating water in the tank.

I am really just wanting to know if these plugs (particularly the #1 plug are so dirty due to double oiling on new powerhead break in, dirty injectors, etc) or if its "normal" and I should just replace and carry on.

[EuropeanAM]

thats fine and dandy but 89 and even 91 are hardly higher octane than 87...

Respectfully- I have to say that's just not true. And having dealt with literally TENS of THOUSANDS of the Direct Injectors used in these engines- I get to see the good, the bad, and the nasty-carbon-laden-ugly. Running higher octane fuels will contribute to an incomplete burn of fuel and the potential for carbon buildup.

If your engine had idled for more than 3 minutes prior to those plugs being pulled, it is not at all uncommon to see a lot of chalky black carbon on the plugs. That will usually clean right up when the engine is run in the 3500-4800 RPM range (where it gets it's best FUEL ECONOMY... also where it RUNS THE CLEANEST).

Optimax engines run the "dirtiest" at IDLE and WOT.

[basshole51]

Respectfully- I have to say that's just not true. And having dealt with literally TENS of THOUSANDS of the Direct Injectors used in these engines- I get to see the good, the bad, and the nasty-carbon-laden-ugly. Running higher octane fuels will contribute to an incomplete burn of fuel and the potential for carbon buildup.

If your engine had idled for more than 3 minutes prior to those plugs being pulled, it is not at all uncommon to see a lot of chalky black carbon on the plugs. That will usually clean right up when the engine is run in the 3500-4800 RPM range (where it gets it's best FUEL ECONOMY... also where it RUNS THE CLEANEST).

Optimax engines run the "dirtiest" at IDLE and WOT.

thanks for the information. The last time out I was running WOT testing a new prop and then idling for 10 minutes waiting on the launch to open up...that would likely explain the plugs ( was also running the Quickstore as I knew it would be one of my last trips out)...when out fishing I typically run on plane in suggested RPM range as my vessel view mobile shows the least fuel consumption in that range.

I will replace plugs in spring as per your winterization suggestions and reinspect again mid season.

[digthemup]

It's been discussed a million times... These outboards were specifically designed to run on fuels up to and including 10% ethanol. Higher octanes burn at a lower temps which can cause your spark plug to foul... Dan

Hey Dan,
Have you asked yourself 'how do these company tuned and manipulated these motors to run on crappy fuel like 10%+-ethanol'? and how much more power could they have put out if they didn't have to retard spark close to TDC to prevent detonation from said fuel? Sad when incompetent government bureaucracy manipulated by lobbyists otherwise known as EPA mandate how manufacturers have to compensate to survive and their products to make it past warranty coverage.
BTW, they call non ethanol fuel, special fuel, but when I used to pump it and check the oil for customers, we call it pump fuel.

[Gamblinman]

Trying to "read" plugs that have been subject to idling before removal is inaccurate and inconclusive. Only way to get a true "read" is to chop the throttle and shut the engine off, trolling motor back to trailer.

[lmoore]

I posted some similiar looking plugs on here a year or two ago. Based on the advice given, I started using only 87 octane, even if it had ethanol. Made a noticeable difference in the look of my plugs. I ran the tank down and the last couple fills this season and used non-ethanol 91. I figure I will be replacing the plugs in the spring anyways and this way I don't have ethanol sitting all winter.

[Dan21XRS]

Hey Dan,
Have you asked yourself 'how do these company tuned and manipulated these motors to run on crappy fuel like 10%+-ethanol'?

No I haven't... I've owned 4 Opti's since 1999 and haven't had a fuel related issue with any of them and we haven't been able to buy ethanol free gas in SW Ohio for eons... Since we've had the lake house in Tennessee I've tried it once and saw no performance gains, so why waste the money???... All I can go by is my experiences, and since I pay the bills... Now if you want to send me one of your credit cards I'd more than happy to... No, I'd still use 10% 87 octane fuels from high volume gas stations because that's what Mercury recommends...

On a side note I did accidentally fill my truck up once with 100% gas and I got 2 miles less per gallon... Dan

[SilverFox579]

I'd still use 10% 87 octane fuels from high volume gas stations because that's what Mercury recommends...

^^^^

Top tier, high volume, E10, 87 octane for the 10yrs, 8mos since first tank with my Optimax and I keep the tank full at all times. No choice here and no fuel related issues. I'm following Don's recommendation, in priority listed, as posted in the FAQ.

[digthemup]

No I haven't... I've owned 4 Opti's since 1999 and haven't had a fuel related issue with any of them and we haven't been able to buy ethanol free gas in SW Ohio for eons... Since we've had the lake house in Tennessee I've tried it once and saw no performance gains, so why waste the money???... All I can go by is my experiences, and since I pay the bills... Now if you want to send me one of your credit cards I'd more than happy to... No, I'd still use 10% 87 octane fuels from high volume gas stations because that's what Mercury recommends...

On a side note I did accidentally fill my truck up once with 100% gas and I got 2 miles less per gallon... Dan

Dan,
Even if you were to run VP fuel it would not make a bit of difference due to you engine tune, which that is what I was talking about in the second part of the question I poses to you.
Nevertheless, the way you flip your rigs and motors is about the same rate my mother in law trades her cars in, so you may never know of the cumulative problems that your mechanic prevents by doing good maintenance on those motors. Keep paying those bills!

[Dan21XRS]

I can't control what the EPA or any other gov't agency mandates... They've never asked me... So I control what I can control... Dan

[digthemup]

I can't control what the EPA or any other gov't agency mandates... They've never asked me... So I control what I can control... Dan

There is 1 thing you control brother, your vote, make sure you exercise that right anytime and everytime. By the grace of Jesus, I will be heading down to TN or KY, and stop paying nearly $4000 tax on our cottage that is just over 1100 sq ft being assessed $235K by NYS town of Lyme.
Be well and be blessed...Franco