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Captain
Posts: 45
Registered: ‎01-14-2019

1985 9.9 evinrude 100:1 Oil

Just bought a 9.9 evinrude. It is from 1985 and calls for 100:1. Original owner has been running as such since new. Should I continue as is, or move to 50:1? Is there likely harm with either? I’m planning on using tcw3 premix, or am also open to mixing xd-100 since o have an etec.90 HP.. suggestions welcome please. Motor runs like it is new.
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Admiral
Posts: 8,435
Registered: ‎07-14-2011

Re: 1985 9.9 evinrude 100:1 Oil

 

 

The 100:1 was only for a few years as corrosion showed up too often if they were used infrequently. In addition, it was only recommended if the motor was not used at full speed very often.

 

A service publication was distributed to dealer to remove the 100:1 decals and suggest that the customer change to 50:1 for better engine protection.

 

One pint of Evinrude oil (or a TC-W3 certified oil) is a 50:1 mix

 

 

 


"There is never just one thing wrong with a boat";
                    -- Travis McGee, main character in a book series by John D. McDonald 


 



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The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.

The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.


Captain
Posts: 45
Registered: ‎01-14-2019

Re: 1985 9.9 evinrude 100:1 Oil

Is there any design differences that you know of for them that makes them 50:1 vs 100:1? I’m tempted to keep on running 100:1 because that’s all the engine has ever seen, and it’s over 30 years old. I have seen yamaha’s that are 100:1 work fine too.