1985 Johnson 15 hp Throttle Plate?

[petermjj]

Hi from a newbie... in the link I think I attached from another post, you can see a cam and roller with a throttle plate in "full throttle" position. In my picture attached, you will see a picture of my engine, at full throttle. The throttle plate is not far enough over, and once I get it started it slowly dies. I'm trying to diagnose the problem... Any ideas as to what is most likely?

 

[oldboat1]

Adjustment is at the other end (i.e., at idle). The roller should just touch the cam at the scribed mark on the cam when you start to throttle up/throttle plate moves open. Below that, the roller will not be in contact with the cam.

Once you have the correct adjustment (the "link and sync"), chances are the wide open setting will be fine. The motor has to be in gear to fully open the throttle, in case you didn't know that.

(Lot's of reasons for poor running -- spark, compression, fuel, and more. Might as well do the roller adjustment first, and see how it runs.)

 

[flyingscott]

+1 on everything oldboat said. You can also look at the gears on the tiller handle see if they are lined up correctly.

 

[racerone]

Slowly dying can be due to a lean condition .----Can be due to crankcase compression leakage.-------Have you done a compression test or any other trouble shooting ?

 

[kbait]

If, when you took the picture, the motor was in neutral ? that cam/roller position is probably normal (safety feature only lets you throttle-up to high idle in neutral). Motor must be in forward gear for your mag plate/cam to advance all the way and push the roller forward to full throttle position. Look up 'link/sync'..basically make sure it's set to just start opening the throttle butterfly as mark on cam lines up with cam follower roller.
Good luck!

 

[petermjj]

Thanks to all! Didn't realize it had to be in gear to move past high idle. I'll check that first. If that does the trick, I obviously need to fix my idle speed to keep it from dying. There are probably a dozen other things that *should* be checked on the motor... but... baby steps. Thanks again -

 

[Newyota]

Adjustment is at the other end (i.e., at idle). The roller should just touch the cam at the scribed mark on the cam when you start to throttle up/throttle plate moves open. Below that, the roller will not be in contact with the cam.

Once you have the correct adjustment (the "link and sync"), chances are the wide open setting will be fine. The motor has to be in gear to fully open the throttle, in case you didn't know that.

(Lot's of reasons for poor running -- spark, compression, fuel, and more. Might as well do the roller adjustment first, and see how it runs.)

​I did the link and sync and was wondering if I did it right?I have it so the throttle plate just moves when the roller is centered on the roller.Is that correct or should it be at the leading edge of the roller?

 

[oldboat1]

Look for the scribed mark on the cam. When the roller touches the mark, the throttle should begin to open. (Adjust the follower/roller so it first touches the cam at the mark when you turn the grip to throttle up.)

It's easier to do than to describe. When you turn the grip all the way clockwise (low idle), the roller will not be in contact with the cam.

 

[Newyota]

Thanks..I was not sure on the actual position of the roller.Saw good video on YouTube but it was hard to see where he had the roller in relation to the scribe mark exactly.I have mine on center.I may have to go back and change it a little..After I replace my impeller.