GAs/Oil Mix for a 40hp Johnson RDSL265

[wackostu]

What is the proper mixture for a Johnson 40 hp RDSL265?

Thanks in advance!

 

[JB]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

I think you misread the model number slightly, stu. I think it might be a RDSL26S. If so it is a 1964 model and uses a 50:1 mix.

 

[1946Zephyr]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

Yep, mine says 50:1 also.

 

[kfa4303]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

You can run 50:1, but I've always run 24:1 in my old Johnson/Big Twin without issue. Be sure you're using Champion J6C plugs too.

 

[wackostu]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

I think you misread the model number slightly, stu. I think it might be a RDSL26S. If so it is a 1964 model and uses a 50:1 mix.

Thanks for clarifying. What does the "S" stand for? Most of the model # I looked at just stopped at RDSL26.

 

[F_R]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

The letter suffix indicates any mid-year engineering changes made to the motor. I know there was a change in the throttle linkage. Maybe others also.

 

[wackostu]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

The letter suffix indicates any mid-year engineering changes made to the motor. I know there was a change in the throttle linkage. Maybe others also.

Thanks!

 

[wackostu]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

You can run 50:1, but I've always run 24:1 in my old Johnson/Big Twin without issue. Be sure you're using Champion J6C plugs too.

Just wondering why the difference. What made you run different then what was recommended?

 

[jimmbo]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

You can run 50:1, but I've always run 24:1 in my old Johnson/Big Twin without issue. Be sure you're using Champion J6C plugs too.

The 40hp was speced with J4J plugs, now J4C. If 50:1 is enough oil for the bearings to run smoothly, 24:1 is not going to make them run more smoothly

 

[kfa4303]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

Just wondering why the difference. What made you run different then what was recommended?

I always like to err on the side of caution. While your specific model may be ok at 50:1, 24:1 offers an extra layer of protection, particularly on motors that may have been neglected over the years. My motor may die, but it won't be for lack of lubrication, and I can always add up to double the volume of straight gas (or any lesser mix for that matter) in a pinch and still be within a safe operating mix. I also prefer the J6C plugs, because I do lots of low speed trolling (manatee zones) and the slightly hotter plug seems to help burn the fuel better, but the J4Cs are fine too.

 

[wackostu]

Re: GAs/Oil Mix for a 40hp Johnson RDSL265

I always like to err on the side of caution. While your specific model may be ok at 50:1, 24:1 offers an extra layer of protection, particularly on motors that may have been neglected over the years. My motor may die, but it won't be for lack of lubrication, and I can always add up to double the volume of straight gas (or any lesser mix for that matter) in a pinch and still be within a safe operating mix. I also prefer the J6C plugs, because I do lots of low speed trolling (manatee zones) and the slightly hotter plug seems to help burn the fuel better, but the J4Cs are fine too.

Thanks for the clarification.