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Johnson 9.9 Timing / Sync hash mark way off.

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louisvillefisherman

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I am attempting to set the throttle sync on my 1988 Johnson 9.9 (J10RCCD) as a step in diagnosing a larger issued I am currently having.

From what I have read, there is a hash mark on the top of the throttle cam (found it) and it is supposed to line up with the roller when the pivoting action of the roller being pushed by the cam results in the butterfly just beginning to open.

My problem is that the hash mark is too far past the roller, maybe a 1/4 inch or so. I would have to turn the throttle way to much in the "power down" direction to be able to get that to line up and I cant because I am already at the lowest idle position on the grip.

I know there is an allen screw on the open end of the cam that essentially makes the cam "fatter" thus effecting when the cam hits the roller, but it does not seem to effect the location of that hash mark.

To visualize , if I were looking into the throat of the carb, the hash mark would be too far to the right of the roller. I would have to turn the throttle backwards (decelerate) quite a ways to get it to the center of the roller, but of course I can not because I am at the bottom end of the throttle twist range already.

What kind of problems would a poorly aligned throttle roller / hash mark create?

And what should I be looking at in order to get that line to come closer to the roller?
 
The problem I am experiencing is major bogging upon throttle up.

Idles great, starts on 2 pulls cold, 1 pull warm.

But when I throttle it, it sounds awful, no power.

I understand that it can be many different issues cause the motor to throttle poorly. I have a list of things I have checked and another list of things I am going to check.

One of those things on the list was throttle linkage sync. I checked, and it is WAY out of spec. I would like to address this before moving to the next item.

For the life of me I cannot figure out how to move that cam more to the left in order to have the hash line up with the cam roller when the butterfly begins to turn. The allen screw on the cam itself is not helping because it only controls the depth of the cam, not the position.

Would anyone know where the idle stop screw is on this motor? I am having a hard time finding it.
 
You can not move the cam to the left it is fixed at the factory and can not / does not need to be moved to the left.---------What is the compression on this motor ?---------There is nothing wrong with the motor if the cam and roller do not touch at idle.May be that the low speed needle is set too lean !----Try adjusting that out 1/4 turn at a time to see if bogging goes away.
 
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racerone said:
You can not move the cam to the left it is fixed at the factory and can not / does not need to be moved to the left.---------What is the compression on this motor ?---------There is nothing wrong with the motor if the cam and roller do not touch at idle.May be that the low speed needle is set too lean !----Try adjusting that out 1/4 turn at a time to see if bogging goes away.
Click to expand...


The motor is a 1988 Johnson 9.9 Model Number J10RCCD.

Racerone,

Since the cam position is fixed, how do I then make that alignment mark line up with the cam? According to everything I am reading, the proper setting is that the hash mark must be lined up with the cam when the butterfly starts to turn. (essentially at the point where cam and the roller make contact and begins to push the roller which in effect opens butterfly is when the mark should be at the center of roller).

My roller will never see the hash mark as it is already PAST the roller, and by opening the throttle it only moves FURTHER away from the roller. If I would only get that hash mark to be slightly to the left of the roller, then I would be able to make that hash line up center to the roller as I throttle it.

I know it is ok for the cam not to touch the roller at idle, that is fine, but the hash mark, that is my problem!

You mentioned the low speed needle. Is this the idle mixture knob that is on the FRONT of the motor that goes into the front of the carb? I have it turned to where the motor idles good. I read this should have no effect on throttle up. Is that not true? I did not mess with it beyond smooth idle. Will certainly play with that some more during next test session. But I do not want to get too far away from this sync issue for now.

A few answers to the other questions:

I do not know the compression as I do not have a tester. Thumb tested (I know, useless) and it pushes thumb off hole. That is on the list of things I will be checking.
I do not have a gap tester, but I did see spark on both plugs. Again, will buy one of those as well when I get to that point.

I know both of those above questions are important, and trust me, I will do them, but I am trying to do the FREE things first, and throttle sync was one of the free items I could check and sure enough, it is not to spec, so before I spend money on tools (comp gauge, spark gap) that I will only use a few times, I want to get this item sewn up before moving to the next item.

Does anyone know how to make the hash mark line up with the roller?

There are dozens of posts, articles (yes I read the leroys ramblings) that say you need to sync throttle, and what a synced throttle looks like (hash in middle of roller at initial butterfly movement) but none of them say how to actually make this happen! Leroy mentions it but only talks about how to "fatten" cam to make the contact, but does not mention how to get the hash there to begin with.

kimcrwbr1:

This motor does not have any controls on the sides, just one knob, and it is on the front of the motor. It is the idle mixture knob.

I really appreciate every ones help, I trust me I am absorbing ALL of this information. Still trying to figure out the sync issue however, and once I get past that I will pick another one of the many items on that growing checklist.
 
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The plate rotates and when that mark sweeps by the roller is when throttle starts to open.-----------Those rollers had a piece of rubber " tubing " on them and has it fallen off by any chance ??--Post a picture of the roller as it is plastic and may be broken.---This adjustment is often mis-understood !!----Idle stop is in the end of the steering handle.
 
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Disconnect the throttle shaft and you should be able to rotate the vertical control shaft so that the cam and roller no longer touch, then synchronize as necessary. There is a ball shaped trunnion I believe that is threaded on the control cable for adjustment to further aid in idle speed adjustment range at the handle, if memory serves me correctly.
 
Just Curious,

I think you win the prize. The ball shaped trunnion was the key. I managed to get everything sync'd by adjusting the throttle cable using the trunnion.

My suspicion is that this motor was converted for remote operation, and then it was switch back to tiller and who ever did the work did not pay attention to the throttle sync and timing plate locations.

I have not had a chance to test the motor yet as it took all night to figure this out and I am at work today but at least that part is done!

A beer (or soda) for you my friend!
 
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