The following (in bold) is from the Evinrude website:
What is the Fuel/Oil mixture for my (Johnson or Evinrude) motor?
- 1958 and prior used 20:1
- 1959 thru 1969 used 24:1
- 1964 and newer use 50:1
- New engine break-in (not direct injection) requires 25:1
Please note that some Johnson and Evinrude Owners Manuals mention 100:1 mixture ratio after the motor is completely broken in, but most experts suggest against doing that. Stick with 50:1 for the 1964 and newer motors.
Models that have working VRO Pumps (Variable Ratio Oilers) do not require oil to be mixed with fuel. The pump is doing the mixing.
Below is some additional information from our friend and frequent forum contributor Joe Reeves:
(Mixture 50/1 vs 24/1)
In years past OMC issued a bulletin that all their engines could use the 50/1 mixture, excepting the 1957 7.5hp model, and many boaters were using that 50/1 mixture in all the older models regardless of horsepower. I lost track of that bulletin unfortunately and if anyone has it, I’d appreciate having a copy of it.
However as time went by, there came about a great amount of discussion as it seemed more than a normal amount of powerheads were being rebuilt in a given time period.
Keeping it short, a rule of thumb was accepted that any engine that had a powerhead that incorporated “ALL” needle, roller, and/or ball bearings on its moving parts (crankshaft, connecting rod, wrist pin) could safely use the 50/1 mixture…… and any engine that DID NOT should use the 24/1 mixture.
Whether this resulted in a drop of powerhead failures or not is not for me to decide…. but why risk it.