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Posted: Sun Jun 21, 2009 8:25 pm
by cookie1
Hi have aquire a Johnson 20 hp outboard 1966 vintage. Have put it in the tank and it runs. Pumps water then stops pumping needs a impeler ok. tickover lumpy then stalls.
I am going to service it, any help on pionts settings how to clean an set the carb would be useful. Any help on workshop manual would be helpful.

Posted: Sun Jun 21, 2009 8:45 pm
by hammyloz
go to it is a forum full of help

Posted: Mon Jun 22, 2009 5:59 am
by jacko69
all i do to clean carbs is to take of the air filter then spray carb cleaner into the carb throught the air intake leave it for an hour then run the engine you will find that this removes any build up of crap in the jets

Dave :D

Posted: Mon Jun 22, 2009 8:06 am
by hammyloz
carb cleaner is ok but you will still be left with spots of varnish inside the carbs as it dont clean it 100% you need to strip the carbs and soak them in a special cleaner and rebuild using new jets etc i have done it a thousand times and it is easy as long as you have the manual to hand

Posted: Mon Jun 22, 2009 11:51 am
by cookie1
Thanks lads anyone got a manual?

Posted: Mon Jun 22, 2009 3:24 pm
by hammyloz
cookie1 seriously go and visit the website i gave you earlier it is a wonderful site

Posted: Mon Jun 22, 2009 10:40 pm
by cookie1
I was able to finf the following information on IBoat and I have posted the following for referance

Replacing the point sets is easy. Physically replace one set at a time. Use the second set as a wire guide to show you where the wires go. To adjust the point gap, rotate the crank shaft until the crank shaft key way aligns with the point sets rub block (the part that contacts the point cam). Set the point gap for .020.
Rotate the crank shaft 180 degrees, and again line up the crank key with the rub block for the second point set and set for .020.

The fiber 'wick' is an oiler. Replace the original with the new one supplied. The felt should contact the point cam and lubricates the cam surface.
You need a suitable puller to get the flywheel off. A harmonic balancer puller will work. Be sure to use Grade-8 bolts.

Then when you reinstall the flywheel it is extremely important that the flywheel and crankshaft tapers be clean and dry and you MUST use a torque wrench to tighten the nut to 40-45 ft/lbs. Ignore this advice and you can just junk the motor because of the severe damage that will occur.

(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.