Older motors, Ethanol, and synthetic oils

[CaneCutter79]

Here's something I ran across after reading up on the the ethanol in outboard motor issue. Newer sythetic oils are thinner but coat better than oils back in the 70's & 80's. Some folks are going from 50:1 ratio to 100:1 because the oil smokes less and reduces cabon/oil build-up in older motors. One guy had been running his older Evinrude motor (115hp I believe) for 3yrs this way with superb results after a rebuild.

I have had my 79 model Evinrude for 2yrs now and did not know I needed to protect the motor from ethanol fuel and now I need a rebuild because one cylinder has low compression. I always use at least 87 octane fuel and sometimes I've tried 93 octane with better mileage results. I assume ethanol in the fuel may have contributed to the leaking gasket I have and now bad piston ring. Now that I know better now, I will protect against in the future with fuel treatment.


So has there been much disussion or experience with using newer synthetic outboard oils in older motors? And is it safe to reduce oil to a 100:1 mix? I'm thinking NEVER EVER reduce but wanted to ask around.

Here is the oil I was looking into...
http://www.amsoil.com/storefront/ato.aspx

 

[wilde1j]

Re: Older motors, Ethanol, and synthetic oils

Use TCW-3 oil 50:1. Ethanol likely didn't cause a ring to fail, but carbon might, as well as lean running.

 

[CaneCutter79]

Re: Older motors, Ethanol, and synthetic oils

After I created this post, I saw the "similar" threads at the bottom. Funny my search didn't turn up those particular threads. I figured there had been much discussion on this. Sorry for the repeat thread.

As for lean running, a bad carb (not bad fuel mix) will cause lean running right? Also not enough lubrication because of bad carb correct? Or am I backwards?

 

[wilde1j]

Re: Older motors, Ethanol, and synthetic oils

Lean is too little fuel and/or too much air (has nothing to do with oil). Lean=lot's of heat=damage, caused by air leaks, crap in carb, etc. Not enough lubrication is an entirely different and unrelated deal.

 

[CaneCutter79]

Re: Older motors, Ethanol, and synthetic oils

Lean is too little fuel and/or too much air (has nothing to do with oil). Lean=lot's of heat=damage, caused by air leaks, crap in carb, etc. Not enough lubrication is an entirely different and unrelated deal.

OK, I'm confused. If you are lean on fuel in a cylinder (not enough fuel from crud in carb), then you are not getting enough lubrication from the fuel mix which also causes the heat damage correct? Lean also shows on spark plugs when they are clean and no oil/carbon on plugs.

How is lubrication not related to a lean cylinder? Thanks for your help by the way (again). I learn more and more on this forum. It's amazing!

 

[wilde1j]

Re: Older motors, Ethanol, and synthetic oils

OK, I'm confused. If you are lean on fuel in a cylinder (not enough fuel from crud in carb), then you are not getting enough lubrication from the fuel mix which also causes the heat damage correct? Lean also shows on spark plugs when they are clean and no oil/carbon on plugs.

How is lubrication not related to a lean cylinder? Thanks for your help by the way (again). I learn more and more on this forum. It's amazing!

No. The damage comes from heat (ever see a piston with a hole burned thru the top)? Has zero to do with oil, or lack of it. Lean running causes very high combustion temps. While too little oil (i.e. mixing too little in the gas), that is not the cause of damage in a lean run cylinder. The primary reason for lean plugs to be so clean is from the heat. You don't burn metal BC it doesn't have lube!

 

[CaneCutter79]

Re: Older motors, Ethanol, and synthetic oils

OK, I see what you are saying now. I realize the hi-temp from cumbustion does more damage. I guess I was thinking they were related and the lube helped cool the motor. When I think about what the fuel mix looks like, how is that enough oil to cool something? (haha) Thanks for the clarification. That makes a lot of sense.

 

[wilde1j]

Re: Older motors, Ethanol, and synthetic oils

You might be interested in how the E-Tecs handle combustion temps. Below 2000RPM, the mixture is so lean, it wouldn't ignite if it wasn't aimed directly at the plug gap. This happens to be the area of best fuel economy also. As the RPM's climb, the mixture is enriched, solely to keep combustion temps reasonable. This is so even with special alloy pistons, designed to handle higher temps. If an E-Tec is run very hard most of the time, the fuel economy will suffer. Oil in an E-Tec is never mixed with the fuel, but directly introduced in places where it's needed.

 

[salar600]

Re: Older motors, Ethanol, and synthetic oils

If an E-Tec is run very hard most of the time, the fuel economy will suffer.

Can I had a question?

What do you mean by hardly uses? Always runing at WOT or an under power set-up?

Also is your statment based on motor degradation or just because wot = more fuel?

Thanks, Mart