2R78R Lower Unit Help

[bigforkbrett]

I have a 2hp Johnson, Model 2R78R. I also have an Evinrude lower unit with the housing part number 326488 that came with the motor when I bought it. I think this lower unit with drive shaft fits a 4hp Evinrude but it looks like it would bolt up if the drive shaft was a bit shorter and had a different spline. The shaft does not fit into the engine splines. Can I purchase the correct shaft an use the Evinrude housing? If not please tell me what the least expensive way is to repair this motor. Thanks for your help!!

[boats.net]

The cases are the same between a 4hp and the 2hp, however the case number is 389066. It seems that the case number you have is for a much newer engine. Your best option is to look for the complete lower unit assembly.