JW 14 ignition-carb question

[Boonie]

I have a Johnson JW 14 3 hp. When i push the  throttle lever all the way to fast, the carb butterfly only opens partially. Why is this happening? Is there an adjustment i need to make?

[fleetwin]

I’m betting the brass throttle cam is bent backwards.  This often happens with the carb linkage is rusted/won’t move, moving the throttle lever just bends the cam back out of the way

3 users thanked author for this post.

aquasonic, Boonie, seakaye12

[Boonie]

Thanks fleetwin. Did some reshaping and got butterfly opening all the way.

where can i get packing for the carb jets . I dont need the whole rebuild kit. Can i make them?

[aquasonic]

It’s interesting this subject came up because I just dealt with this same problem yesterday on a 1960 Lightwin. When adjusting the throttle cam for link and sync. the throttle was way behind the ignition advancement and there was no adjustment left in the slotted cam connection.

Looking closely at the cam in cross section and the upper 90 degree bend was clearly larger than 90 degrees meaning it was bent backward toward the powerhead. The link and sync adjustment was off about an inch from the factory mark.

By using a large screwdriver as a lever, I was able to carefully bend the bronze throttle cam forward little by little until the adjustment was right on the mark. This is an important adjustment that often gets overlooked.

[Boonie]

Aquasonic

can you explain the link and sync adjustment and what to look for as far as the factory mark. Im not clear on how this procedure works?

[aquasonic]

I will try to explain the link and sync adjustment. The idea is to achieve the best combination of throttle and ignition advancement for best performance. The adjustment to the cam is made by the two tiny cap screws that take a 5/16″ wrench. The two screws attach the throttle cam to the underside of the magplate and they straddle the ignition advance lever.

The port side of the throttle cam has a slotted connection that allows for the cam adjustment inward and outward as needed. By trial and error, observe the ignition advancement lever/butterfly relationship to see the amount and direction of needed adjustment. Then loosen the cap screws. Adjust the cam as needed within the slotted connection, then tighten the cap screws. Next, advance the ignition lever to observe the effect of the adjustment. Repeat as necessary.

The proper adjustment for your Johnson JW model is when the ignition advancement lever is between the two marks, the carburetor butterfly just starts to turn. Focus on the shaft for the butterfly because there is a lot of play in the rest of the linkage and the butterfly is the last component to turn.

The first of the attached pictures shows the two factory marks one is under the “L” and the other is just past the “W” on the word “SLOW”. The second picture shows the advancement lever between the marks. This is the position where the butterfly shaft should just start to turn.

[Boonie]

Thanks aquasonic. That clarifies things for me. My throttle butterfly starts to open at the begining of the start word. No more adjustment. I guess next step is to do some cam bending?  I would post some pics but when i try it says file to large?

[crosbyman]

it is all in the BOOK !

https://watercraftmanuals.com/outboard/johnson/manuals/johnson-302231.htm

 

Joining AOMCI has priviledges 🙂

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