Oil/ gas mixture for older Johnson 9.9?

[Michael P]

Hello to all of you outboard motor gurus! I just bought an older Johnson 9.9, model # 10R75C, and I think it was produced in 1975. I have a couple of questions: Was this motor produced in 75? What is the proper oil/gas mixture? I have found manuals for model # 10R75 will this book cover my motor? And last, this motor has low hours and has not been run in a couple of years, anything I should know befor firing her up and putting it in the water?<br /><br />Thanks for any help.<br /><br />Mike

 

[Boatist]

Re: Oil/ gas mixture for older Johnson 9.9?

WV Mike<br />The oil mix is 50 to 1. 16oz of oil for 6 gallons of gas. Yes it is a 1975. Manual looks good to me. <br /><br />I would squirt a shot of oil in each cylinder with the plugs out then crank one time. Check plugs and gap to .30 then put plug back. I also would open oil drain and see if lower unit oil looks good with no water or you chould just change it. Start it on the muffs with the cover off to make sure motor starts and warms up but does not overheat. No tell tail on this motor but does have a exhaust relif port on back near cover latch. Motor should warm to point can hold finger on block for 3 to 4 sec then thermostat opean and water will come out above the cavatation plate. I have a 1975 15 hp and on muff almost no water comes out exhaust relif at back. If you run in a garbage can or on the water then should get some spray out relif port.<br /><br />If it runs ok warms up ok and does not over heat time to take her out. I would not use old fuel in motor.<br />If oil.

 

[Michael P]

Re: Oil/ gas mixture for older Johnson 9.9?

Boatist, Thanks a ton for the RE. I have a 14' deep v that was manufactured in 1967 this Johonson will be the perfect motor for her. I am also 2/3 done building a, Devlin design, duck boat and while this boat calls for a larger motor the 9.9 should make a good choice for the "first time out" run.<br /><br />Again, many thanks for the info.<br /><br />Mike

 

[Boatist]

Re: Oil/ gas mixture for older Johnson 9.9?

WV Mike<br />I also have a 1967 14 foot Aluminum Klamath I use my 15HP on. It is ok for two but need more power for 3 and gear. Only difference between Your 9.9 and My 15 HP is the carburetor.