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I spent last weekend as a volunteer for a Seattle SeaFair event. I was one of two whaler tenders for the unlimited hydros and F1 race boats. So I was motoring around the pits for 4 days.
I have a 1989 Mercury Blackmax 150. My motor has oil injection and it functions well enough that the motor runs well, doesn't foul plugs and the 2 gallon oil tank is about 1/2 full after 45 gallons of fuel burned. Meaning the mixture is approximately 45 to 1, this sounds pretty good, but why the smoke? Compression was shop checked before purchase, 22 hours ago. (Hobbs time)

But wow does she smoke. Those poor media types when I started it, since they were right by me most of the time at the dock. I don't mind some smoke, this is seems like a little much.

At idle the smoke on the water is a continual light stream of smoke and at power it is tough to see any at all, but it is there.
The mechanism operates well and looks like it is in good repair.
But as you can guess, I wonder if it might need an adjustment of the injection pump.


I don't have any pictures of it smoking, but here is the motor at the races.
http://farm8.staticflickr.com/7134/77...ab68_b.jpg

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Those motors do smoke. I have two of them on my boat but I burn oil at a consistent average of 60:1.

Se sure the oil pump mixing linkage on the motor has not popped off and allowing the oil pump to mix at maximum richness. That happens to one of mine once and it smoked a LOT more until I snapped the linkage back on.

I also use only Mercury/Quicksilver Premium Plus oil. That helped cut down the smoke the Quicksilver Premium oil produced for the original owner of my boat.

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We ran Evinrude XD50 oil in our twin Mercury 150's on our Guardian. That premium oil greatly reduced the amount of smoke they produced over standard TWC - 3 oils, standard Quicksilver oil included. When never found the Quicksilver plus oil locally so I can not comment on that but, it likely produces the same results as the Evinrude XD50 oil does.

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I checked the pump linkage and it seems fine, it operates well, without binding or roughness. I have been using cheap oil so maybe this is some of the issue.
After doing the math, although it is just an estimate, the usage is around 45/1 or 50/1, so it looks good there.
But, holy cow does she smoke.
I just learned about Sal A's "decarbonizing" treatment and some other easy to find products and thought it might be a good idea as well as upgrading to a high quality oil.
One more question; how long should I expect the oil pump life span to be? I hear quite a lot of belly aching about pumps and "don't trust them" discussions, although this is a 1989 motor and it has been run quite a lot. I ran snowmobiles for years with no failures ever. Even 30 year old machines worked perfectly, so it might be an understatement to suggest that I am a touch skeptical about the fear of failing injection pumps.

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In my 1992 Johnson 90 I went from generic West Marine TWC-3 oil to OMC XD-30 and noticed a significant decrease in smoking, even at start-up.

John K.

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You could try the XD100 evinrude oil, Almost no smoke, but at $40 a gallon I wouldn't recommend it. Sounds like the injector needs and adjustment. It should be at least 50:1 usually.

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No, that does not look good. At the very richest, that motor should not be using more oil than a 50:1 ratio, and with the variable ratio oil mixing the motor is designed to use, it should be more like 60:1 if the motor is used hard, and less if a lot of low speed operation is normal.

Oil use at a rate of 45:1 is an extra quart of oil up in smoke for every gallon of oil purchased.

Maybe it's just an estimating error, maybe not, but I would not be so quick to dismiss the evidence of that cloud of smoke.

Smoke at start up and during warm up is normal. Once the motor is warm, there should not be that much visible smoke.

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Regarding the type of oil used, I recommend the use of Mercury (or Quicksilver) Premium Plus Oil for the conventional Mercury two strokes. As I said above, my motors definitely benefited from the use of this superior oil.

Do not make the mistake others have made after switching to a two stroke oil with better additives and think that this oil is actually smokier. It is not, but because of the additives it has in it that help keep the motor clean, there may be an initial period after switching where the motor seems to produce MORE smoke. This is the just the oil cleaning out the carbon deposits left by the cheap oil.

Give it time; the motor will clear and appreciate what you are feeding it.

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To give credit where credit is due, there has been mention of a shock carbon treatment prescibed by a Whaler user. This advice came from the late Sal DiMercurio, a real character and friend of mine, not Sal A(rnuk).