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Need Help Johnson 20HP 1971 Outboard

J

jtblas

Member
"Hello,

I placed a post on

"Hello,

I placed a post on this forum about a week ago regarding these problems I m having with my Johnson 1971 Outboard. I have the motor semi-working and I will explain.

In order to start the motor, I typically can start it without the choke on. Having the choke on sometimes does not start the motor. What I think part of my problem is is that the idel adjustment knob unscrews itself with the vibrations. I have figured out that holding the idle knob allows the motor to run better. There is still some white smoke coming out of it and I believe that I might need to check my gas/oil mixture. Can anyone provide pointers?

Regards,
Joe"
 
"Joe... The slow speed needle

"Joe... The slow speed needle valve is held in place by a nylon bushing, the bushing that you see right at the front of the carburetor.... it's the very first thing that needle valve goes into.

It sounds like you have the old type nylon bushing which is usually white or black which is inferior and loosens up within a short period of time. That looseness also allows the carburetor/engine to draw in air which leads to mixture problems.

You need to purchase the RED bushing, part number 315232 which really grips that needle valve and prevents it from turning.

(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.

http://stores.ebay.com/Evinrude-Johnson-Outboard-Parts-etc?refid=store"
 
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