Evinrude 2 cycle oil

Hey everyone,

This is something that is bothering me.

Besides my 170 CC, I own another boat, it's older (27 years) 14 aluminum job and it has a older (27 year) 35 hp Evinrude motor on it.

I just got it back from the mechanic, and among other things he told me I was running my gas/oil mixture to rich, okay, and that I should only use Evinrude 2 cycle oil for my mixture- huh???

He said if I didn't, I would keep fouling plugs, and lose performance.

I did some research on this and I did learn that there is a difference between TCW-II and TCW-III oils, with big variations in the different brands of TCW-II oil, but not so much with the TCW-III oils, except for price. An Evinrude 2 cycle oil is +/- $30.00/gallon other brands are $12-20/gallon.

Why I am confused is, this engine was built before there were differnet types of 2 cycle oils, and it has seem to run fine for all the years I have own it, why the big change in things now?? Is it because the blends in gasoline are different now then they were then? Is there something in Evinrude's 2 cycle oil that makes up for these differences?

I'd like some input on this before we head for northern Canada to go fishing next week.

Help me out here folks.

Thanks
Kevin

[Putershark]

Couple of things...

• No matter which type or brand of oil you use, you need to "always" make sure the oil to fuel mixture is correct, period... Even running too much of any high grade oil can foul out the plugs and even faster if you do a lot of idling / trolling.
• Unlike a 4 stroke engine that you can (though I would not) run a lower grade of oil in and just change it more often... You do not have such slack with a 2 stroke engine. It burns it's lube oil and as such, needs a oil that will lube and cool as well as burn off, this without leaving behind a lot of deposits... As I have always said, if you cannot afford the oil, then you cannot afford the engine This for using high quality lubes and fuel is the cheapest insurance policy you will ever buy and much less expensive than any blown power head.
• I would go with the most cost effective high grade oil you can run (I prefer Synthetic) with the highest level if detergent fuels you can find in your area. Just like the Fram Ads say "you can pay a little now, or a lot later" still holds very true.
• You do not though need to run just Evinrude oil to prevent such fowling from taking place. I would also make sure that that spark plugs are of the correct heat range for that engine AND that the engine thermostats are in working condition. If not, the engine can and will run either too hot or too cold for the design intent.
• I suspect that this engine has a carb, and I would make sure that you keep the carb clean using some spray throttle body cleaner. I say throttle body cleaner since it will not strip off any metal coatings (clear coats) that the factory may have used / sprayed inside the carb intake. Many harsh carb cleaners will strip off and remove such (carb cleaners can slowly destroy fuel injected throttle bodies if used) so by using a throttle body spray cleaner, you will still get it clean along with any air bleed jets that may get clogged, without such long term worries... Having the carb intake or air bleed jets get dirty though, can cause the engine to "load up" on fuel at idle and dump in more fuel than needed much like it was running with the choke on all the time. That will also cause the spark plugs to foul out very quickly.

Thanks for the good advice.

I run this engine at idle for long periods of time (trolling), and have always use a good / high octane gas. I have never had problems with plugs fouling or adjustments before, the only thing I can figure is that I ended up added more oil than needed the last time I filled the tank.

The big thing here for me was the oil type and having the mechanic say that you should only run specific type oil in your gas it seemed to be a reach.
From all the research I did the TCW-3 oils are pretty consistant across the board, so I am going with a Pennzoil oil that formulated for older motors, it meets or exceeds all the specs on TCW-3 oils, and cost less than the Evinrude oil.

Guess we will see - may have to paddle some if I'm wrong.