johnson 1963 JW 18 R

[mrhabitat]

The 3 HP jw-18 starts easily, runs well at hi speed but moving the lever below the START position it will stall
I’ve moved the low speed mixture screw both clockwise and counter clockwise but that had no effect. Thoughts?

[Buccaneer]

Low speed fuel circuit plugged.

Prepare to be boarded!

[fleetwin]

Perhaps the carburetor throttle shaft is stuck/binding….In other words, it is not closing fully…These engines won’t idle if the throttle plate is stuck open….

[Tom]

Interesting responses here. I had one with the same problem. I fixed it by reengineering the butterfly advance. The butterfly was closing too much at idle. That motor ran great and idled extremely well after the mods.

But as noted above, the clogged idle system is more likely your culprit, as long as the gasket inside the bottom of the carburetor is in good shape.

Looking back, I suspect my motor had a carb from a different model on it, one with linkage that wasn’t designed for the motor.

T

• This reply was modified 2 years, 7 months ago by Tom.

[crosbyman]

http://www.outboard-boat-motor-repair.com/Evinrude%203%20HP%20Lightwin%20Outboard%20Boat%20Motor/Evinrude%20Johnson%203%20HP%201952-1967%20Carburetor%20Tune-UP.htm

Joining AOMCI has priviledges 🙂

[billw]

Probably a dirty carb. However, verify good strong spark on both cylinders and that the plugs are not in question. (New or known good used.) Those engines WILL run on just one cylinder but stall at lower speeds.

Long live American manufacturing!

[need2fish]

I’ve read Frank R recommended using a fine wire to make sure the low speed circuit is clean.

In my experience using air on fine passages is a bad idea — the force of the air may compact the junk in the passage and result in something even harder to clean out.

[Mumbles]

You could have some crud buildup at the bottom of the bowl blocking the passage shown on the left. This passage supplies fuel to the low and mid range circuits in the carb and it must be clear. The corresponding passageways in the carb body must be clear and clean to.

[Author]

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