How do I tune my 83 Johnson 35 hp

Bryanjlb

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Feb 4, 2013
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I have a 1983 Johnson 35 Hp. It has not been ran in over a year. I replaced the water pump, spark plugs, cleaned the Carburetor, and changed the lower unit oil. I got it running, but it idles high. It also runs good. I am trying to tune the engine. There is a nob on the Carburetor for the air and gas ratio I think. The nob got turned and messed with during work on the engine. How do i reset that knob. Also need to turn idle down.

While removing the lower unit my lower i pried on the back of the unit, and now i have a little water leaking out the back. Do I have to buy a new casing, or is there a gasket I have to get?
 

jasper60103

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Sep 18, 2008
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Re: How do I tune my 83 Johnson 35 hp

Bryan,
follow the procedure below for the initial carb adjustment.
As for the "idles high" problem, is the tiller handle rotated fully CCW?
If that's the case, there should be an adjustment screw at the rear of the tiller handle to
allow to adjust idle speed slower.

edit: Above, I assumed you have a tiller model, but that may not be the case?

jasper

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(Carburetor Adjustment - Single S/S Adjustable Needle Valve)
(J. Reeves)

Initial setting is: Slow speed = seat gently, then open 1-1/2 turns.

Start engine and set the rpms to where it just stays running. In segments of 1/8 turns, start to turn the S/S needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running.

Eventually you'll hit the point where the engine wants to die out or it will spit back (sounds like a mild backfire). At that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

Note: As a final double check setting of the slow speed valve(s), if the engine has more than one carburetor, do not attempt to gradually adjust all of the valves/carburetors at the same time. Do one at a time until you hit the above response (die out or spit back), then go on to the next valve/carburetor. It may be necessary to back out "all" of the slow speed adjustable needle valves 1/8 turn before doing this final adjustment due to the fact that one of the valves might be initially set ever so slightly lean.

When you have finished the above adjustment, you will have no reason to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
 

Bryanjlb

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Feb 4, 2013
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Re: How do I tune my 83 Johnson 35 hp

There is no tiller. It is a steering column. In the back of the motor there is a set screw with two rods , is that the idle set screw. I have the motor running smooth now. To tune it better do i start by turning it all the way to the left or right?
 

Bryanjlb

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Feb 4, 2013
Messages
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Re: How do I tune my 83 Johnson 35 hp

Is there a lower unit gasket? I'm leaking a little water out of back of lower unit. Or is that ok?
 

jasper60103

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Sep 18, 2008
Messages
2,055
Re: How do I tune my 83 Johnson 35 hp

Is there a lower unit gasket? I'm leaking a little water out of back of lower unit. Or is that ok?

There's no LU gasket. It's not unusual for motors to leak some where the gear case connects to the mid section. If its pumping good water I wouldn't worry about. IMO.
 

jasper60103

Commander
Joined
Sep 18, 2008
Messages
2,055
Re: How do I tune my 83 Johnson 35 hp

There is no tiller. It is a steering column. In the back of the motor there is a set screw with two rods , is that the idle set screw. I have the motor running smooth now. To tune it better do i start by turning it all the way to the left or right?

Are you referring to the carb S/S needle adjustment or idle set screw adjustment?
 
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