Getting a 2-stroke to run cleaner?

[zuren]

I'm not a hippy-treehugger, but running my newish-to-me motor in a tank at home (50 gal. trash barrel) was a little eye opening on just how dirty a 2-stroke motor can be.  I understand that running a 2-stroke at idle is not running it at peak efficiency, but the oily scum that ended up floating in the top of that barrel was stomach turning.  Plugs are new, gas is ethanol-free from Mobil, oil is Quicksilver mixed at the correct ratio.  This engine does smoke some when it is running.  Should I suspect something isn't running right, or is this to be expected from a 1986 Mercury 2-stroke running at idle? 

Other than replacing the motor with a 4-stroke, I'm researching other ways to help a 2-stroke outboard run cleaner.  I know there is a lot of debate over oil, but I would be interested in knowing if others are running something different (at different ratios) and what their experiences have been with smoking and any kind of discharge in the exhaust?

Thanks!

 

[CedarRiverScooter]

Same result here. Oil scum in barrel. Lots of smoke when cold. Maybe you can run it on muffs at home long enough to warm it & then it would burn cleaner at the lake.

I don't think synthetic oil is any better. Maybe olive oil would be better for the ducks but not so good for your motor . . .

 

[GYPSY400]

It is the nature of the beast. 2 things you can try:
Replace the thermostat and tune the carburetor appropriately, so it can run as lean as possible.. if its running cold all the time it wont burn fuel efficiently.
Run 100:1 mix when trolling with good synthetic oil. This topic will stir up some debate but I feel that the oils nowadays can sufficiently lube at 100:1.. you can run a second fuel tank that you use during trolling, and then switch back to your main 50:1 for high speed runs..

 

[Weldorthemagnificent]

I can't imagine there's a guy out there who hasn't had a twinge of guilt after running an outboard in a barrel.

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[MrGiggles]

If that motor has been sitting, it'll be worse than usual.

When it's warmed up and has been run hard, you should not get any smoke, or very little under normal operating conditions (not trolling). Some smoke on startup or during extended idle is normal.

 

[Pappy]

First off welcome to the forum.
Secondly, there has already been some good information coming your way.
Your engine has to run up to the thermostat temperature at idle. Usually around 135F or so on most engines. If not the engine will not burn the incoming fuel/oil mix as efficiently as it is capable of.
Third, a proper mixture has to be established. A rich mixture at idle will leave more unburned fuel on the water and in your mid-section on the engine.
Now.....Oils.
BRP has an oil that is an environmentally friendly oil. XD-100. It is one of the best oils out there as far as protection goes and it breaks down, leaving it about as good as it gets for the environment.
Always go with the fuel oil mixture rate the engine manufacturer list or even a little richer if you run weeds or shallow water to protect the powerhead in the event of an overheat. Some oil manufacturers will claim you can run at a leaner mixture with their oil. When everything is perfect that may hold some water but if you are running a touch lean, hotter than normal, etc. then all bets are off. Get the picture?

 

[Shaugh]

My understanding is that any modern TC-3 outboard oil is designed to quickly break down. It's not as bad as it looks.... That's why it's white when it comes out.. it's already been emulsified or made to mix with water and break down.

 

[zuren]

I can't imagine there's a guy out there who hasn't had a twinge of guilt after running an outboard in a barrel.

Glad to know I'm in good company.

First off welcome to the forum.

Secondly, there has already been some good information coming your way.
Your engine has to run up to the thermostat temperature at idle. Usually around 135F or so on most engines. If not the engine will not burn the incoming fuel/oil mix as efficiently as it is capable of.
Third, a proper mixture has to be established. A rich mixture at idle will leave more unburned fuel on the water and in your mid-section on the engine.
Now.....Oils.
BRP has an oil that is an environmentally friendly oil. XD-100. It is one of the best oils out there as far as protection goes and it breaks down, leaving it about as good as it gets for the environment.
Always go with the fuel oil mixture rate the engine manufacturer list or even a little richer if you run weeds or shallow water to protect the powerhead in the event of an overheat. Some oil manufacturers will claim you can run at a leaner mixture with their oil. When everything is perfect that may hold some water but if you are running a touch lean, hotter than normal, etc. then all bets are off. Get the picture?

Thanks Pappy! Thanks for the welcome, and this is the exact type of info I'm looking for. Regarding XD-100 being more environmentally friendly, I see some of the physical attributes mentioned in many places (smokeless, ashless, etc.) but it is usually a 1-liner in a marketing piece. Is there a place that I can find more detail on the XD-100 oil? I've poked around the Evinrude, BRP, and XPS Lubricants websites, and see nothing mentioned. Except for the fact that this oil is sold everywhere, it is almost as if it doesn't exist (no formal product website).

Thanks!

 

[JL8Jeff]

Idle will always give you more smoke as will a restart. Depending on your situation and how you run your boat, you can run 100:1 mix which will help cut down on the smoke, but if you need to use full throttle often, I wouldn't recommend it. I run my boat upstream around 1/2 to 2/3 throttle (it's the smooth spot and quietest rpm range) and I've been running synthetic at 100:1 in two different boats/motors for the last 12-15 years with no problems. I've been running premix for a long time as the vro pumps always seem to crap out. I'm never in a hurry and our max range between wing dams is around 3 miles so just don't need WOT and I hate the extra noise especially out of a jet. I've used the Amsoil synthetic and now the Quicksilver synthetic.

 

[Weldorthemagnificent]

There is a SDS available online as a pdf. Says it's not readily biodegradable and an environmental hazard. That being said, everything I read about it, it seems to be cleaner and less smoke and ash. I'm thinking it's worth a try.

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[zuren]

My understanding is that any modern TC-3 outboard oil is designed to quickly break down. It's not as bad as it looks.... That's why it's white when it comes out.. it's already been emulsified or made to mix with water and break down.

This would definitely make me feel better if it is true. I just did a search, and a few articles I find on TCW-3 oils and the environment is this:

http://www.nmma.org/certification/oil/tc-w3 (I have some reading to do! "Satisfying EPA requirements" is mentioned on the front page, but I would like to know more).

https://www.practical-sailor.com/blog/two-new-green-marine-products (TCW-3 oil that touts its environmental friendliness; can this logic be applied to any oil carrying a TCW-3 certification?)

Thanks!

 

[DaleH]

I 2nd a well tuned/maintained engine and running XD-100 oil.

 

[jeff925]

add 2 strokes

 

[DaleH]

add 2 strokes

Nope, false ... 'fake news', haha :wink: ... as in the bigger motors (and probably holds true for smaller blocks too), the Evinrude E-Tec and newer G2s et al are CLEANER than 4-stroke OBs! To be as clean, 4-stroke OBs would need to add catalytic converter, as you're only thinking about the oil in the water and not factoring in the exhaust emissions.

 

[Weldorthemagnificent]

From what I understand, decarbonizing an older outboard can help rings seal up better and make it run better. I'm far from an expert, just a tinkerer but I'm going to try this on the 9.5 evinrude I picked up last fall . Then a good quality oil like xd100 might be worth the extra coin to keep it running clean.

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[Pappy]

Good point!
However there is a lot of boat ramp caliber knowledge about how to do it properly.
I have written about it before as well as others so there is a lot that can be looked up on this subject.
I would recommend OMC Engine Tuner or the Merc brand. It is a very powerful cleaner compared to what everyone thinks is "the bomb" for cleaning.
In order to use it properly the instructions have to be read and adhered to. It is not a squirt and go type of cleaner.
Start the engine and let it come up to temp.
Once at temp start squirting the Tuner down the throat of the carb(s) while running the engine just fast enough to not stall. Remember the engine is at it's warmest at or just above idle.....
On small engines use at least a half can. On 3-cylinder and above use a full can.
Things are going to get very smoky.........
Once completed drop the idle and use the Tuner to flood the engine to a stop.
Let the engine sit overnight with the tuner in the cylinders and on the rings.
Next day re-start the engine and clear the majority of the Tuner from the engine.
Add some extra oil to the pre-mix or the fuel supply. Why? Because a lot of carbon is about to be coming loose and going through your engine. Extra oil will help flush it away while increasing protection from scuffing.
Run your engine in the water on the boat and keep the power levels and RPM down a while to help clear the carbon then run as you normally do.

 

[turbotodd]

A carbureted 2 stroke is not going to run clean; which is exactly why the EPA hates them. What you've noticed (scum in the test tank) is perfectly normal. EFI with fuel and oil and ignition timing management is the only way to reduce the oil and fuel contamination; however it comes at a cost (weight, complexity, cost, etc) and not many of us are going to pay MORE for an old 2 stroke motor when we can get a cleaner running 4 stroke that is lighter weight and for less cost. I ran a 90 2 stroke in the test tank today, ran for about 10 minutes at idle and just above idle. The scum on the top of the water was certainly eye opening! You outta see what a 2 stroke 200 and 225 do. They're all so bad that after a test run at idle and just above idle that I've got to spend time afterwards cleaning the scum out of the tank as well as off of the motor's leg and lower unit, and since I'm on the clock (dealer work) the consumer gets to pay for it unfortunately. But on the other side of it, if I dont' clean the leg and foot off, they get mad so as a tech, it don't matter either way, I'm the bad guy.

 

[nowgrn4]

Great advice from pappy on the engine tuner, I've been a true believer of it since the 70's. I've always drilled small holes in the breather cover in line with the center of each carb orifice and used small stainless screws to seal the holes. Removing the screws is so much simpler than removing all the bolts on the cover to use the tuner. Tuner is great for a yearly clean out on your 2-Stroke weed trimmers, blowers and chain saws too.