50:1 or 40:1

[skipper47]

I am looking for a service manual for my 20hp 1973 Johnson, in the mean time can someone
tell the correct fuel/oil ratio please.
As I said in another I put it on a stand (in water) to see if it starts and runs which it did fine,
I used a 40:1 ratio should I use a 50:1?

 

[racerone]

At 40:1 your grand kids will be running it years from now.----At 50:1 it will also run for many hrs.----Fact---2 strokes and lubrication are not well understood.

 

[timguy]

I see Racer beat me by a few minutes. I run 100:1 with this stuff, but catch hell from most here on the Forum. If you can get Amsoil, you will be golden. I have used it for over 40 years at two remote camps in NW Ontario Canada. Mostly in OMC motors. In earlier pre bearing (bushing) crankshaf motors.......pre 1965 OMC's. I mix at 50:1 for heavy work like freighting, but 64:1 for normal running.

 

[skipper47]

Thanks racerone.

 

[skipper47]

Thanks also timguy.

 

[timguy]

I have this little 6hp Fisherman Evinrude with over 3500 logged hours...(I keep records). It still runs perfectly.....and with original head gasket and water pump impeller, all original fuel lines, including primer bulb and original steel 6 gallon tank. Never sits outside unless it's running, or on the boat. Never has run in weeds. Why should that matter? Weeds can block water intake, both adding debris and stressing impeller.