1959 Johnson 18HP motor help (rich/lean adj)

Greetings. I just picked up an 18 HP Johnson dated 1959 that ran strong the first time out. Amazingly I am the 2nd owner of this motor. It ran great like I said however the red (slow) adjustment seems to have stripped out and loosened up counterclockwise 3 plus revolutions. I keep the white (ast) dial set between 4 and 5. I was only able to obtain enough rpm's to keep the motor barely running. I returned home and saw that that had loosened up and I tightened it up and set it back close to 3 on dial. The dial seems to be stripped now and wont hold tight. Is there something I can do to fix this setting? Is the carb shot now because of this? First time boat owner so any help or guidance would be greatly appreciated. Does anyone know of any good mechanics that can fix this up here in Wisconsin if it gets to that point? Thanks in advance!

Re: 1959 Johnson 18HP motor help (rich/lean adj)

you need a carb rebuild kit, with new packing for the needles. how to's are in the TOP SECRET FILE, top of this forum.

Re: 1959 Johnson 18HP motor help (rich/lean adj)

tashasdaddy said:

you need a carb rebuild kit, with new packing for the needles. how to's are in the TOP SECRET FILE, top of this forum.

Click to expand...

That carburetor does not have threads inside for the needle to screw into. Instead, it has a threaded sleeve in there, along with two packings, and it is all held in with the packing nut which should be tightened enough to hold it snug but still allow turning with a reasonable amount of force.

Your packings are shot, which is why it spun on you. Replace them and readjust.

The numbers on the knobs are totally meaningless. The idea is to adjust them for best running, then put the knob on with the numbers mid-scale.

Re: 1959 Johnson 18HP motor help (rich/lean adj)

Good morning. So basically I just back that small nut out and replace the packings that are on that sleeve then? Sounds easy enough. I will give that a shat and see what happens. Obviously having that dial unscrew 3 revolutions would be the culprit for the motor not coming up to full RPM right?

Re: 1959 Johnson 18HP motor help (rich/lean adj)

I got that piece out with no problems. Anyone know where the packings go? They were gone, not sure where to start. Any suggestions?

Re: 1959 Johnson 18HP motor help (rich/lean adj)

jemrami9 said:

I got that piece out with no problems. Anyone know where the packings go? They were gone, not sure where to start. Any suggestions?

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1. Slide a couple of packings onto the needle.
2. Screw the sleeve on the needle a couple of turns.
3. Poke the assembly into the hole till it hits bottom.
4. Screw in the packing nut, pushing the packings in with it.
5. Tighten the packing nut just slightly beyond finger tight.
6. Now screw the needle all the way in with your fingers (do not force it in tight), then back it off one and a half turns.
7. Tighten the packing nut some more till there is enough friction on the needle to hold it from vibrating around.
8. Start and warm up the motor (on a boat, in the lake).
9. Run at slow idle in gear and turn the needle to the right till the motor coughs, then turn it back to the left just enough that it quits coughing.
10. Install the knob at mid-scale. Double check that the packings are tight enough to prevent it from vibrating around.
11. Done. Give yourself a pat on the back.

Re: 1959 Johnson 18HP motor help (rich/lean adj)

Good evening!
Just got home, did everything as you had stated and it worked just like you said, thanks for the help! I appreciate it!