1986 Merc 115 hp out board not run for 18-20 years .

[Johnanderson]

Just picked up a boat w a 1986 merc 115 out board been setting 18-20 yrs . Setting sheltered and in very nice condition. Yes the old gas will be drained n lines flushed. Want to remove the carbs main jets n clean reinstall because gas was still in the tank. Im not filmiller with those carbs on there. There's nothing on the bottom of the carb bowl but there is something in the front bottom of the carb bowl . Is the main jet accessible thru there ? Anything else I should do with the carbs ? Install new fuel filters ? Water pump impeller ?

 

[GA_Boater]

Take a look at this waking a sleeping outboard thread. It is forJjohnsons and Evinrudes, but the basic information still holds true.

Does the motor turn? You still might squirt some 50:1 premix in the plug holes to lube the rings and cylinder walls.

Welcome to iboats!

 

[Johnanderson]

Did shoot some WD 40 in the cylinders then hand turned the motor. All cylinders gave a good puff with my thumb over the plug holes. The motor really looks like new except not run in years. Worried about the gas gummy up inside the carbs ? Also not going to chance the oil pump . Going to disconnect it and mix the oil n gas . Going to use Amsoil synthetic 2 stroke oil. Anyone know how many ounces per gallon ?

 

[GA_Boater]

50:1 is the ratio. I use one of these to add oil to the fuel. No thinking on my part. :smile:

 

[Chris1956]

Firstly I would recommend using a certified TC-WIII oil, vs amsoil, which is not certified, 16 oz oil to 6 gallons regular gasoline is the correct mixture.

Secondly I would recommend you clean all three carbs and rebuild them with new gaskets, inlet needle and seat and new floats. The main jet is under the brass hex bolt on the sidebowl carbs. There are pinholes in the carb throat that are part of the idle fuel circuit. These clog easily, and must be clear to function. Initial idle screw setting is 1-1/2 turns open.

Thirdly I recommend you purchase a OEM service manual, as you will not find many shops who will work on that motor. I would then check the idle pickup timing and max spark advance to see if it is within spec.

Happy Boating