Question about a 100:1 oil ratio

[boater1234]

Hey fellows this is not a debate of what is right and wrong it's just simply a question about a 100:1 oil ratio for a 15hp 2stroke yamaha or any smaller outboard that may call for a 100:1 oil ratio.

My question is has anyone ever heard or experienced a motor with problems or locking up from a 100:1 oil ratio when they were using it full time?I know that johnson and evinrude changed it yrs ago from 100:1 to 50:1 because when the motors sat for a long peroid of time there wouldn't be proper lubrication sitting in the engine and would cause corrosion or the motor would seize up.

I'm talking about a motor that will not sit for longer then like 2weeks at the very most if that.I will probally use it at least once to twice a week.I'm not asking if it is the right ratio as i know everyone has their opinions on that,i'm asking for anyone who has actually uses their motors full time,has never let it sit for a long peroid of time.Has anyones motor seized up at all or given them any problems at all that they know of from a 100:1 oil ratio?Thanks.

 

[kodibass]

Re: Question about a 100:1 oil ratio

I have been repairing outboards for a few years now, I just had a yamaha 15 brought in owner sad they were running at wot & engine started making a clicking sound which got louder and louder, and then the engine just stopped running, they tried to restart but engine was locked up, said she was running mix at 100/1, I'll start tearing it down later this week and I'll post my findings. I have had several 2 strokers with scored cylinders, snapped ring etc, But learned allllllllllllllllllllong time ago you never know what could'v been mixed and sent to the engine to drink, contaminated fuel in one form or another is my bread & butter

 

[aerobat]

Re: Question about a 100:1 oil ratio

i have a 5 hp 2000 yamaha kicker and use 100:1 without any issues- and the motor sits often for a long time being a kicker.

in our marina we have a workboat , a pontoon with a 1999 yamahs 6 hp which also burns 100:1 and is used more regularly , also without any issues.

so nothing to report about oil related failures, i also never heard about definitivly oil related issues when the correct mixing ratio is used.

 

[~Nickolas~]

Re: Question about a 100:1 oil ratio

The second half of this season I switched to Amsoil 100:1 in my 72 Evinrude 85 and so far so good. I like how the engine responds to this oil or ratio myself. There is so much discussion on this and most people I converse with about this ratio wouldn't touch it and say STAY AWAY from 100:1 or you will be getting another motor. Well then I have talked to some old racers who have been using it for years and love it and haven't had any issues at all. So as the old saying goes 6 to 1 half dozen to the other... I always say regular maintenance is the key. If you take care of your motor it will take care of you. I always mix it up real good and also add an ethanol treatment to every tank of gas I use. Every season I torque the cylinder head(s) to spec and also change the gear case oil along with a fuel filter. I take good care of my outboards and they take care of me. I don't think 100:1 is going to ruin a motor IF it is in good working order in the first place. Too much oil isn't good either. Most of us are not out running WOT 24/7 and running ethanol gas with no additive to combat phase seperation. I will continue to use 100:1 because it works for me. If for some reason I blow an engine or throw a rod... No biggie I say as a power head for an older motor isn't that expensive. I picked up a real nice one on ebay for 100 bucks with excellent compression and that's the motor I am running at 100:1. So this is one boater that does run his motors hard and I haven't had any issues but a more positive experience...

 

[steelespike]

Re: Question about a 100:1 oil ratio

It appears Yamaha has been running their premix motors at 100:1 for some time.
I don't follow the Yamaha section very closely but haven't seen any mixture issues .
My beef with 100:1 is there isn't any room for error.
If the carb starts running lean or someone misses on rhe mix.Bingo cooked.
When my 88 50 Evinrude was a pup I accidently ran it at 100:1(don't ask) nothing happened till my son had his buddies up for a weekend of skiing, 2 months later.Fortunately he stopped running it when it made noise. Just cost $800 to do the top cylinder.I put the bill above my 2 stroke oil shelf.Its still going strong today over 20 years later.Of course at 50:1


I wonder if that 15hp failure might have been an over heat.

 

[JimS123]

Re: Question about a 100:1 oil ratio

I think we just answered this question twice in the past few months. Nevertheless,...

I had the same dilema so I asked my local Yami OB dealer. He's had the franchise along with OMC since Yami first came into the US. They have been in business since 1946 and the current owner is the grandson of the founder and a master Yami tech. His answer to me was that he's never had an engine fail on 100:1 and he recommends that to everyone. His only caveat was to use either Yami or OMC oil. (yes, that's what he sells, be that as it may)

 

[F_R]

Re: Question about a 100:1 oil ratio

Any time an engine fails, you can bet the diagnosis will be oil failure of some sort. No matter what actually caused the failure.

And any time it won't run, the diagnosis will be Ethanol. No matter the real reason it won't run.

 

[Bob_VT]

Re: Question about a 100:1 oil ratio

Any time an engine fails, you can bet the diagnosis will be oil failure of some sort. No matter what actually caused the failure.

And any time it won't run, the diagnosis will be Ethanol. No matter the real reason it won't run.

You forgot the impellar Your statement is 100% correct!

 

[JimS123]

Re: Question about a 100:1 oil ratio

Any time an engine fails, you can bet the diagnosis will be oil failure of some sort. No matter what actually caused the failure.

And any time it won't run, the diagnosis will be Ethanol. No matter the real reason it won't run.

A buddy lent his 9.9 to a friend of his who had never run an outboard before. When he brought it back he said it was running a little rough and told my buddy it probably needed a tuneup. When I saw the hole in the block I asked him to call his friend and ask him how much oil he put in the tank when he refiilled it. The friend said "you put oil in the tank?".....LOL.

Anyway, when I pulled the head I was actually surprized how the internals looked. The pistons, cylinders and all internal parts were shiny and slick as a whistle. Not a sign of any gas or oil anywhere. It looked so clean....like a brand new engine that had never been run before. Well, except for the 1000 little bits of metal fragments that used to be a connecting rod!

That WAS an oil failure.....LOL.