Fuel - Oil mix 100 : 1 ??

[Jerry_NJ]

I have purchased a used 9.9 HP Yamaha 2 Cycle Circa 1995. I can not find a user manual on the web but the web based user manual fo the 1998 engine prescribes a fuel/oil ration of 25:1 for break in, 100:1 thereafter.

Going below 50:1 makes me uncomfortable, and here's why: I purchase a fishing boat outfit in 1986 with a Johnson 9.9 HP 2 cycle and the Owner Manual specified 75:1 after breaking. I used that boat for about 10 years but will guess the engine had no more than 200 hours on it when it started giving me problems. I took it to the local OEM and boat dealer and asked them to repair. They called me back and said the engine was "shot" and not worth repairing. I purchased a new Evinrude 9.9 HP 2 Cycle to replace it. I believe 200 hours for a wear out is way too early and the engine failure was caused by too little lubrication.

So, how do I accept a recommendation to go 100:1? Maybe that assumes Synthetic oil, I don't think the manual was strong on that point.

My current Yamaha is an older engine but it was a back-up engine and has very few hours on it, looks like new. So I'd run it in the rich 50:1 for a few hours while I think about the 100:1 ratio. The engine looks new, and starts on a pull or two, runs well, but I suspect some water pump problems (impeller).

 

[Georgesalmon]

Re: Fuel - Oil mix 100 : 1 ??

stay with 50:1 forever. Synthetic or not. Any oil rated TCW-III

 

[jbjennings]

Re: Fuel - Oil mix 100 : 1 ??

Ditto.

 

[JimS123]

Re: Fuel - Oil mix 100 : 1 ??

My Yami requires 100:1, but after reading forum recommendations I switched to 50:1. Now it smokes too much. I asked my dealer (who has sold and serviced Yamis since they came into the USA) and he snidely asked why i don't just follow the owner's manual. He said he has never seen one that failed because of too little oil.

Maybe Yamaha Motors knows more than we do. I'm back to 100:1 and after 3 more years she runs just fine.

 

[JB]

Re: Fuel - Oil mix 100 : 1 ??

We are all scared of 100:1 mix because it was such a disaster when used on OMC outboards in the late '80s. Cost them a ton because of corroded steel internals when stored.

The Yamahas appear to survive 100:1, but:

More than needed is harmless, less than needed may be fatal. That is why we often recommend 50:1 for the Yammies.

 

[nwcove]

Re: Fuel - Oil mix 100 : 1 ??

i have an early 80's omc with the 100:1 decal on it, but its never been ran at 100:1.( always mixed at 50:1 + a little more oil) the only thing thats ever been touched on the motor was the head gasket.....no carb kit, no impeller, still has the original plugs. sure it drips oil from the exhaust after three or four hours of slow trolling but its nothing a quick wipe doesnt clean up. ( i know.....its time for an impeller!!)
im sure that yamaha torture tested those motors at 100:1, and came up with a number of hours....just past the warrantee.....where the power head would fail.
so why not over oil it? as mentioned, it wont hurt it. jmo

 

[JimS123]

Re: Fuel - Oil mix 100 : 1 ??

i have an early 80's omc with the 100:1 decal on it, but its never been ran at 100:1.( always mixed at 50:1 + a little more oil) the only thing thats ever been touched on the motor was the head gasket.....no carb kit, no impeller, still has the original plugs. sure it drips oil from the exhaust after three or four hours of slow trolling but its nothing a quick wipe doesnt clean up. ( i know.....its time for an impeller!!)
im sure that yamaha torture tested those motors at 100:1, and came up with a number of hours....just past the warrantee.....where the power head would fail.
so why not over oil it? as mentioned, it wont hurt it. jmo

Wow...30 year old spark plugs! Must be a record.

 

[nwcove]

Re: Fuel - Oil mix 100 : 1 ??

Wow...30 year old spark plugs! Must be a record.

yep.....can post pics if it makes a difference! thought the original impeller was more impressive tho. lol ( not sure if 30 year old plugs are a record? probably not even close)

 

[foodfisher]

Re: Fuel - Oil mix 100 : 1 ??

What failed at 100:1? Would 50:1 have prevented the failure?

 

[JB]

Re: Fuel - Oil mix 100 : 1 ??

What failed at 100:1? Would 50:1 have prevented the failure?

They ran okay but when stored the internal steel parts corroded due to inadequate oil coating. 50:1 would definitely have prevented this.

 

[aerobat]

Re: Fuel - Oil mix 100 : 1 ??

Maybe Yamaha Motors knows more than we do. I'm back to 100:1 and after 3 more years she runs just fine.

i also do not think we should teach a father how to make children . i have a yamaha 5 hp kicker and run only 100:1 without ANY issues.

when yamaha says 100:1 we should run 100:1 , period.

a buddy in our marina got a new 15hp 4stroke honda and wanted to have checked valve clearance by the honda dealer after first 10 hours because he read that in a forum ( honda does not call for that after 10 hours ) . the dealer laughed and said he should read less and go boating, refused to do the not needed work .

 

[dingbat]

Re: Fuel - Oil mix 100 : 1 ??

I got to laugh:loco:
Manufacturers know nothing about their products.
It is all a conspiracy to get people to buy new motors.
Need more oil. It could not possibly been damaged by running lean.

 

[Jerry_NJ]

Re: Fuel - Oil mix 100 : 1 ??

Great thread, especially read as a thread. I must have forgotten to check the "instant email"... wonder why I can't set that as an automatic condition.

Well, no consensus it seems, regardless of all the Rank involved. I was an enlisted man in the US Navy (too) and never trusted Rank anyway : ( Well I had to trust the Pilots when I was on one of their airplanes : )

I believe there is some truth to manufacturer building just enough quality to outlast the warranty... tough to control closely, as is so obvious now in cars/trucks which come with a 10 year 100,000 mile warranty. I don't know what the typical small outboard warranty is these days.

I appreciate the experience shared and think I'll continue my practice of 50:1 with the error leaning toward 55:1 and not worrying if it is closer to 60:1.

 

[RogersJetboat454]

Re: Fuel - Oil mix 100 : 1 ??

How long does a manufacturer stay in business if they keep selling outboards that break down right after it gets out of warranty?

Forget 50:1, why not old school 24:1, or even 16:1? It worked back in the older engines, must be still be fine now. We can apply knowledge gained from engines designed by a different manufacturer, decades beforehand to something else, right?

Yamaha has been building various engine powered stuff for almost 60 years. They didn't stick around by selling products that only last the warranty period. I think they know what they're doing.

Now if you'd excuse me, I'm off to buy a few quarts of MobilOil Gargoyle Arctic for my Ford Focus....

 

[jspriddy]

Re: Fuel - Oil mix 100 : 1 ??

I really don't know what to think. As I said in another thread (yours, Jerry), I would think Yamaha had a vested interest in their engines lasting as long as possible. I'm in business myself, and I do everything I can to insure products I sell last as long as possible, sometimes including free maintenance, if I think it's warranted. I think Yamaha is smarter than trying to achieve some kind of "planned obsolescence", just to sell more motors. Look how long it took Kia, and to a certain extent, Hyundai, to overcome bad reputations.

As I understand automatic oilers, they oil more the higher the rpm's are. I guess if I wanted to run up and down the water wide open all the time, I'd stay with 50:1. But the way I boat, sometimes running hard a few miles, and then idling around, I just don't know.

I have a weedeater that runs 100:1 and it does fine after several years. My boat motor does smoke a lot with 50:1, but like others here, I cannot bring myself to run 100:1. I'm seriously considering about 75:1 and let the chips fall where they may.

John

 

[greenbush future]

Re: Fuel - Oil mix 100 : 1 ??

My etech sips oil at such a low volume it scares me, but I have to run with what the manufacture says, and I do. Darn motor gets better mileage than anything I have ever ran too.

The other side is, no engine ever seized by having too much lube, so if you feel better, run it at 50/1

 

[jspriddy]

Re: Fuel - Oil mix 100 : 1 ??

How long does a manufacturer stay in business if they keep selling outboards that break down right after it gets out of warranty?

Forget 50:1, why not old school 24:1, or even 16:1? It worked back in the older engines, must be still be fine now. We can apply knowledge gained from engines designed by a different manufacturer, decades beforehand to something else, right?

Yamaha has been building various engine powered stuff for almost 60 years. They didn't stick around by selling products that only last the warranty period. I think they know what they're doing.

Yeah. 16:1 is what my 38 year old chainsaw runs, and it still runs fine (actually, the engine had to be redone about 20 years ago. Lack of lubrication?)

Now if you'd excuse me, I'm off to buy a few quarts of MobilOil Gargoyle Arctic for my Ford Focus....

Is this what you pull your "1976 Rogers Custom Boats 18' "Bonneville" W/ Chevy 454/ Berkeley 12JC" with? You probably have to run about 8:1 in it?

John

 

[RogersJetboat454]

Re: Fuel - Oil mix 100 : 1 ??

Yeah. 16:1 is what my 38 year old chainsaw runs, and it still runs fine (actually, the engine had to be redone about 20 years ago. Lack of lubrication?)



Is this what you pull your "1976 Rogers Custom Boats 18' "Bonneville" W/ Chevy 454/ Berkeley 12JC" with? You probably have to run
about 8:1 in it?

John

:noidea:...

 

[jspriddy]

Re: Fuel - Oil mix 100 : 1 ??

:noidea:...

Just joking with you, man. I got your point, however. Everything changes, used to run 16:1, then 50:1...so why is everyone so reluctant to go 100:1? I agree, but I just cannot bring myself to go that route, yet. As I said above, I don't think Yamaha would risk their reputation in such a manner.

I had a mental image of your boat behind a Focus-one of those "moving catastrophes" you see on the internet.

have a good day,

John

 

[RogersJetboat454]

Re: Fuel - Oil mix 100 : 1 ??

Just joking with you, man. I got your point, however. Everything changes, used to run 16:1, then 50:1...so why is everyone so reluctant to go 100:1? I agree, but I just cannot bring myself to go that route, yet. As I said above, I don't think Yamaha would risk their reputation in such a manner.

I had a mental image of your boat behind a Focus-one of those "moving catastrophes" you see on the internet.

have a good day,

John

Gotcha...
Sarcasm sometimes doesn't always make it through clearly with just words on a screen...

I'll bet the old timers who ran the old outboards on 16:1 ND 30 weight had a hard time wrapping their head around a 50:1 ratio when most of the outboards in the 60's went that route. Things evolve over time, but sometimes it's hard to let go of the tried, and true.

FYI, the Focus is run on a 6:1 ratio, but for some reason I have a hard time with converters plugging up. Still trying to figure out why...
Jet boat gets pulled with a Smart For Two...