As many of us know OMC has over the years made recomendations on ratios and then turned around and recended the recomendations. This has led to some confusion. Some time back a member posed the question, what year did OMC switch from the 24:1 ratio to the 50:1 ratio? I had a service bulliten from that period, so I posted it in order to answer the question. Joe Reeves asked me to keep an eye out for a service bulliten regaurding using 50:1 in earlier models. Joe, I am still looking, I haven't forgot. Today while searching for info to help another member I came across another interesting S.B. Here is what it says.<br /><br /> Evinrude Service Bulliten No.622<br /> Sept 17 1963<br /> 50:1 Fuel ratio<br />In a press release which went out late in August it was stated that the newly specified 50:1 gas-to oil ratio could also be appied to the 1963 model Evinrudes.<br /> This statement is at variance with instruction contained in all 1963 owner manuals, and also our statement in Evinrude Dock Lines and should be withdrawn.<br /> Accordingly, if you have advised any of the owners of 1963 models that it will be all right to use the 50:1 gas/oil ratio in any 1963 or earlier models which you may have sold them please be sure to correct this statement and tell them that they should strictly follow the 24:1 gas/oil lubrication instructions given in the 1963 owner manuals. <br /> <br /> Evinrude motors Richard Bayley<br /> Service Promotion Manager<br /><br /> Joe Reeves, This isn't the S.B or printed material we are looking for but it does suggest it's existance. I will keep looking.
