Try this link. I have gotten many questions answered from them. I have a 1977 70 hp Seahorse I mix 40-1 never had a problem. Hope this helps.
http://www.ganotech.com/

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I've got a Johnson Seahorse 4 hp from the mid-70's(I dont have a manual or know the exact year of the motor) that I'm trying to get back in business,Does anyone know the proper oil/fuel ratio?Some have told me 30-1,others 50-1.The model number is:4R76M and the serial number is:E4377549.Any help would be greatly appreciated,Thanks,Darealbigcat
Try this link. I have gotten many questions answered from them. I have a 1977 70 hp Seahorse I mix 40-1 never had a problem. Hope this helps.
http://www.ganotech.com/
I googled the of the name and model and found a post for a 1973 model that was 50:1
Thanks for the help,I really appreciate it.Darealbigcat
The instructor at the OMC service training centre told us that the older models can all use a 50:1 mix using OMC oil
