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will that still apply if it has had a good few Hours?
My Evinrude 50hp is 50-1 My 4hp Yamaha is 100-1. Manuals for both don't mention changing the ratio due to age. All you would do if you change the oil/petrol ratio is possibly upset your carb settings and weaken or richen the mixture depending on whether more or less oil was used. Both options could be bad for your motor.
Dave.
 

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I have been told by 3 seperate outboard engineers, that the 100:1 mixture so beloved of Yamaha, is OK when the motor is new, but keeping that mixture will encourage premature wear (built in obselesence maybe)?
I have taken their advice & switched to 50:1 mix;)
blueskip
 

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Johnson 20hp takes 50:1 premix.
 

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And so what your saying surenuffandyesido ? is that i should change my mix on my 1983 25hp yamaha 2 stroke from a 100.1 to 50-1 as of the age of the engine.
 

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No just saying my Evinrude is 50-1 and my Yam 100-1 as recommended by the manufacturers irrespective of age or use.
I have no idea what your year of Yamaha motors petroil ratio would be recommended by the manufacturer.

To be clear though oil ratio should not need to change as it gets older or more used. The notion that a fraction more oil in the mix is going to take up wear in a 2 stroke motor is a bit of a red herring. If that is what you are thinking? All it may do as I said is to reduce the amount of petrol by adding oil in the mix which would make the motor run on the lean side. (less petrol per cycle) Which could be bad for the motor and cause poor running, misfiring etc.

Try signing up to this forum. http://forums.iboats.com An absolute mine of information. It covers all makes of motors in seperate sections for each make. Post the question, someone will fill you in, or browse or do a search I'm sure you will get the info you need.
Dave.
 

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Its 3 Outboard engineers who said it! I know my way around an outboard, enough to service my own motor, but this is advice I have had from PROFESSIONALS, who say it.::rtfm:
If the vast majority of 2 stroke outboards run on a 50:1 mixture, what RADICAL engineering method has been used, to say that just ONE out of them can run on a mixture that is HALF the oil mixture of the others? Extraterrestrial Technology maybe? "I dont fink so" !
You carry on with your 100:1 mixture if you like. but I am sticking with the pro's who say 50:1 after 12 months!
blueskip
 

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Its 3 Outboard engineers who said it! I know my way around an outboard, enough to service my own motor, but this is advice I have had from PROFESSIONALS, who say it.::rtfm:
If the vast majority of 2 stroke outboards run on a 50:1 mixture, what RADICAL engineering method has been used, to say that just ONE out of them can run on a mixture that is HALF the oil mixture of the others? Extraterrestrial Technology maybe? "I dont fink so" !
You carry on with your 100:1 mixture if you like. but I am sticking with the pro's who say 50:1 after 12 months!
blueskip
so how does that work then if its an autolube yamaha?? have the whole oiling system recalibrated after 12 months. I'd be very very cautious. changing from 100:1 to 50:1 after 12 months will defiantely damage one thing - a 2 year or longer warranty

I've ran out of petrol on my yam and plugged a tank of 50:1 and it was far from happy. Do it for a long period your going to gum up lots of things that weren't designed for that much oil, the gumming will settle behing piston rings forcing them eventually to stick for one thing. The reed valves will glaze and gum up and not work effectively starving the engine of even more fuel

If I were a cynical person (!) it might be a good idea for "pro's" to advise this, potentially more engines to fix! Ask them to put it in writing, especially if they are an authorised dealer/service centre
 

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Its 3 Outboard engineers who said it! I know my way around an outboard, enough to service my own motor, but this is advice I have had from PROFESSIONALS, who say it.::rtfm:
If the vast majority of 2 stroke outboards run on a 50:1 mixture, what RADICAL engineering method has been used, to say that just ONE out of them can run on a mixture that is HALF the oil mixture of the others? Extraterrestrial Technology maybe? "I dont fink so" !
You carry on with your 100:1 mixture if you like. but I am sticking with the pro's who say 50:1 after 12 months!
blueskip
No argument from me Blue. Just giving my experience.
Keep on doing what you are happy and confident with. :)
Most old time recommendation for running in an engine was to increase the oil initially then reduce it once run in.
Dave.
 
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