Gas Mix-100/1 or 50/1??

[pscrabber59]

Just bought a 1995 Two-stroke Yamaha 6hp(6msht). Orig. owner said he always ran 100/1 gas mix like the owners manual says to do. Now that i have the motor shall i continue to run 100/1 or would it be better to run 50/1 mix? I have only run the motor for a few mins. and it seems to run pretty smooth on that 100/1 mix

any comments appreciated

 

[robert graham]

Re: Gas Mix-100/1 or 50/1??

Stick with the 50:1 mix for lubrication and corrosion protection.

 

[JimS123]

Re: Gas Mix-100/1 or 50/1??

When in doubt, follow the Owner's manual. If still in doubt, check with the Manufacturer to see if they updated their recommendations since the motor was built.

 

[JB]

Re: Gas Mix-100/1 or 50/1??

When in doubt, follow the Owner's manual. If still in doubt, check with the Manufacturer to see if they updated their recommendations since the motor was built.

In principle, I agree with Jim. However:

1. 100:1 mixes have proven unreliable in protecting engines in storage. OMC backed out of the 100:1 issue very quickly. I don't know if Yamaha ever did or if they bothered to notify owners.

2. Lubricating any engine is like watering a horse. More than she needs is pretty harmless; less than she needs will kill her.

If I had that outboard I would run 50:1 in her.

 

[pscrabber59]

Re: Gas Mix-100/1 or 50/1??

JB- I have never owned a horse but i agree with your analogy.
Should i do a gradual mix over time or just start with the 50/1 right away.

 

[JB]

Re: Gas Mix-100/1 or 50/1??

I would go to 50:1 immediately, pscrabber.

 

[nwcove]

Re: Gas Mix-100/1 or 50/1??

im with jb, and dont be alarmed when you see black oil and goop coming from the exhaust when the motor is out of the water, it wont hurt anything nor is it a sign of problems. ( i have an 85 rude that i bought new, has the 100/1 decal on it.i only ever mixed it 50/1, two friends bought the same motor new and stuck with 100/1......mine is the only survivor, and is still a first pull motor, even after 8 months of storage.)

 

[JimS123]

Re: Gas Mix-100/1 or 50/1??

In principle, I agree with Jim. However:

1. 100:1 mixes have proven unreliable in protecting engines in storage. OMC backed out of the 100:1 issue very quickly. I don't know if Yamaha ever did or if they bothered to notify owners.

2. Lubricating any engine is like watering a horse. More than she needs is pretty harmless; less than she needs will kill her.



If I had that outboard I would run 50:1 in her.

I speak with some experience, take it for what its worth.

Yes, OMC backed off to 50:1, but the reason was attributed to corrosion during severe Winter storage, not due to engine failure due to lack of lubrication. (per my OMC factory buddy - not my personal knowledge).

When I bought my 2007 Yami I broke her in according to the factory specs. After breakin I stuck with 50:1 based on what the gurus said on this forum. That was my second mistake - listening to a forum. The first was buying the Yami in the first place and not being patient enough for the E-tec to make it to my neighborhood....but thats another story.

After awhile of not being happy with the performance, I consulted with my local dealer and he yelled at me for putting too much oil in. He's a Master Mechanic, owns the dealership and has had a Yami franchise since they first came into the US. He said he never had a failure with 100:1.

Anyhoo, I switched to 100:1 in 2010 and have found less fouling and less smoke and overall smoother idling, etc. Regardless of what OMC did, Yamis factory specs call for 100:1 to this day.

 

[Sea Rider]

Re: Gas Mix-100/1 or 50/1??

Or run 75:1 if you are not sure about 100:1

Happy Boating

 

[boltonranger]

Re: Gas Mix-100/1 or 50/1??

I speak with some experience, take it for what its worth.

based on what the gurus said on this forum. That was my second mistake - listening to a forum...

After awhile of not being happy with the performance...

I switched to 100:1 in 2010 and have found less fouling and less smoke and overall smoother idling, etc. Regardless of what OMC did, Yamis factory specs call for 100:1 to this day.

Less fouling. - Many things can cause fouling
Less smoke. - 2 strokes should smoke.
Smoother idling. - You didn't buy it to "idle" around did you?

You're not going to experience a "failure" with 50:1 that would have been avoided with 100:1.
That's certain. Regardless of any other factors.


As to the comment about the forum itself and it's Guru's.
Well I'll just assume you're having a bad day.

This forum and the knowledge it's longtime posters impart stands on it's own merit.
I don't know where I would be as a boater/captain/mechanic without them.
-br

 

[JimS123]

Re: Gas Mix-100/1 or 50/1??

Smoother idling. - You didn't buy it to "idle" around did you?




This forum and the knowledge it's longtime posters impart stands on it's own merit.
-br

As a matter of fact, I DID! Lots of time spent trolling for muskys at dead idle. Using 100:1 as the book and dealer recommended has solved the smoking and fouling issue. In contrast, my older Evinrude will run all day at idle with 50:1 and experience no problems at all. Go figure.

I concur about all the knowledge on these boards and how much they help others (me included). But, for every 5 that know their stuff, there is another one that posts answers that simply are wrong, because of bias or whatever. My point is....if the Manufacturer says one thing and somebody else says the opposite, better be careful who you believe.

 

[JB]

Re: Gas Mix-100/1 or 50/1??

You say that listening to this forum was your second mistake. If iboats is such an unreliable source why should anyone listen to you??

 

[JimS123]

Re: Gas Mix-100/1 or 50/1??

You say that listening to this forum was your second mistake. If iboats is such an unreliable source why should anyone listen to you??

I didn't say it was "such an unreliable source", I said "some" are unreliable.

Since I'm an anonomous person and you have no idea whether I'm reliable or not, maybe you shouldn't listen to me either!

As far as this thread goes, my main point was to listen to the Manufacturer. They are the opnes that have the vested interest in you.

 

[nwcove]

Re: Gas Mix-100/1 or 50/1??

quote"As far as this thread goes, my main point was to listen to the Manufacturer. They are the opnes that have the vested interest in you."


not to be pro or con on anyones opinion, but i guarantee that no manufacturer (nowdays) wants thier motors to last forever.....that would be bad for business, they also dont want them to break in a short time....bad for business also.(but from experience with new everyting...from cars to electronics.....when the warantee is over...the problems start!....they have it down to a science) maybe ive just been lucky mixing a 26 year old 100/1 motor at 50/1..from day one, with 95% of run time at slow idle. i can only recall ever replacing the plugs once. extra oil is messy and smokey, but my little 4.5 still works like new!

 

[Sea Rider]

Re: Gas Mix-100/1 or 50/1??

Don't get it, if you already knew that Yam manufacturer states 100:1 for that engine why are you inquiring second, third thoughts about 50:1 uses ? Just stick to your owners manual, that's what manuals are for, dont they ?

Happy Boating

 

[nwcove]

Re: Gas Mix-100/1 or 50/1??

Don't get it, if you already knew that Yam manufacturer states 100:1 for that engine why are you inquiring second, third thoughts about 50:1 uses ? Just stick to your owners manual, that's what manuals are for, dont they ?

Happy Boating

......im glad i didnt stick to the owners manual.....jmo, 100/1 leaves no margin for error , or the slightest carb issue. to me...its all about what you want from any motor. run it hard for "x" amount of hours at "100/1" (or any other recommended mix)...and feel ok that its going to fail after a few years, or mix it heavy and have it last twice (or more) as long as the manufacturer had figured the motor would.

 

[JB]

Re: Gas Mix-100/1 or 50/1??

"That was my second mistake - listening to a forum."

This is exactly what you posted. No "some" about it.

I agree with you in principle about following the maker's advice. . .and I said so. I might well be the "guru" who suggested that 50:1 is lower risk than 100:1, regardless of what the maker said. The leader in the industry said 100:1 risked damage in long term storage and withdrew 100:1 spec. That was true then and it is true now.

Your third mistake is bashing the very platform you seek to use.

I would use 50:1.

 

[Outsider]

Re: Gas Mix-100/1 or 50/1??

The leader in the industry said...

Uhhh, I believe that industry leader went bankrupt because their engines wouldn't stay in one piece.

It's a 6hp, foul a plug and you're down 50% in cylinder effectiveness. Gum up the carb and you're a raft, or a dock queen. Don't believe I'd be too quick to throw the manual away ...

 

[aerobat]

Re: Gas Mix-100/1 or 50/1??

i am running a 2000 yamaha 5 hp as a kicker with 100:1 without any single issue . but for sure you can run it with 50:1 as well.

excessive over-oiling ( but far more than 50:1) will result in fouled plugs, lower power , excessive smoke and carbon deposits in engine. the "extra" oil will not lubricate the engine better but will be just burned off with visible smoke . what seems right to me is that over oiling will not result in an immediate failure but under oiling will do so.

when an engine is recommended to 100:1 i do not see any benefit running it more rich beyond supporting the oil industry since you use more oil. when it comes to storing you may just run the last tank of gas richer and all will be fine.

 

[Sea Rider]

Re: Gas Mix-100/1 or 50/1??

All manufacturers test their engines heavily looking for fatigued parts or parts that have failed, when everything is OK, final product goes into market, definitely have tested engines to the limit with 100:1 ratios, are not cracy guys recommending any oil ratios.

So to be equitative with safe ratios use :

100:1 for idling/fishing
50:1 normal/full throttle operation

Anyway, going back to the original poster, it's only a 6 HP horse, how much time at full throttle operation will he be running his engine ? probably 1/2 to 3/4 to throttle to move a light boat and to potter around; if a engine fails under the writen factory recommended 100:1 ratio, you could always sue the Company...

Happy Boating