9.9 Johnson Timing Plate Adjustment

PutPut1

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Jun 9, 2013
Messages
23
Hi there,

I have an older (74-76, can't remember) 9.9 Johnson. Yesterday as I was at about 2/3-3/4 throttle, it got stuck there, I had to kill it as it is stuck at a high enough throttle where I can't shift from forward to neutral. Now looking at it, the timing plate is rotated too far counter-clockwise so when I'm at idle on the tiller, the motor is actually at about 3/4 throttle. The arrow on the timing plate is way too far to the right (if looking from the front) of the roller connected to the carb. I know now I have to adjust this to get the arrow to line up with the roller while at idle, but I'm not sure how.

How do I adjust the plate?

Thanks
 

OptsyEagle

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Sep 13, 2006
Messages
1,356
Re: 9.9 Johnson Timing Plate Adjustment

If the motor is a 74-76 the throttle cam is adjusted by the two 5/16" nuts positioned, very badly, under the flywheel on the starboard side. You simply loosen those nuts and move the throttle cam forward or back. The proper position is for the mark on the throttle cam to be in the center of the carb's roller when the roller "just" touches the cam. This operation synchronizes your spark timing over all the RPM ranges of your motor and is pretty important to obtain top performance...and as you have noticed, to run right.

I say that the nuts are positioned poorly because unless the flywheel is removed, the thickness of most 5/16" wrenches will not allow you to get at them. What I did was to take a file and file down one of my thinnest wrenches to be used for this purpose. This is where one of your wrenches that was made in China, come in handy. Their crappy steal tends to file quicker. Good luck.
 

the machinist

Senior Chief Petty Officer
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May 7, 2002
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711
Re: 9.9 Johnson Timing Plate Adjustment

Another thing to look at is possibly your throttle linkage may have become disconnected off the connector peg of the timing plate.
 

PutPut1

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Jun 9, 2013
Messages
23
Re: 9.9 Johnson Timing Plate Adjustment

Okay, I managed to find those two nuts yesterday and I can move that plate in and out. And yes I did have to grind down an old wrench. However I still need to rotate the entire plate clockwise at least an inch, maybe more. Right now its turned so far so I can't even take the motor out of gear. Could this be done by disconnecting and reconnecting the throttle linkage?
 

oldman570

Lieutenant Commander
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Mar 25, 2011
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1,615
Re: 9.9 Johnson Timing Plate Adjustment

The link for Leeroys Ramblings at the bottom of The Machinist post will give you a detailed way to set the carb and timing plate, and other easy to understand info that is for your motor. You should be able to find out most info for the motor with just a little reading. I have used it on several motors of the same vintage and when done as the info states have had very good results.
JMO
Oldman570
 

OptsyEagle

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Sep 13, 2006
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1,356
Re: 9.9 Johnson Timing Plate Adjustment

Perhaps you have the wrong throttle cam on your motor. Many will have a part number right on the cam. If you gave us the part number we could confirm if it is the right one. Your model number that is on the transom bracket would be good as well, for this. Also if you had a picture of the situation, those always help.
 

PutPut1

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Jun 9, 2013
Messages
23
Re: 9.9 Johnson Timing Plate Adjustment

Alright, I'll have a look through that link.

As for it being the wrong plate, it is possible but it was fine before. It was just on Saturday where it somehow rotated to far. I'll see if I can get the part number and a picture.

Thanks
 

OptsyEagle

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Sep 13, 2006
Messages
1,356
Re: 9.9 Johnson Timing Plate Adjustment

Did the teeth in your tiller arm perhaps realign in the wrong spot. Lift up the tiller arm and see if they are engaged where they should be. Also, take a look at the machinists post. I am not sure what he is alluding to here but it does sound like something has become disengaged.
 

PutPut1

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Jun 9, 2013
Messages
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Re: 9.9 Johnson Timing Plate Adjustment

I never even thought of checking those teeth. I'll look at the throttle linkage too, if that's all it is that would be nice.

I read through part of the LeeRoy's Ramblings. It looks like I may be able to adjust this plate but the flywheel has to come off so I'd like to avoid that if possible
 

PutPut1

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Joined
Jun 9, 2013
Messages
23
Re: 9.9 Johnson Timing Plate Adjustment

Well everyone I managed to get it fixed last night. Thanks very much for all your help.

Stupid thing is what was causing it. As I was playing with the tiller handle I noticed something had to be obstructing the plate from rotating all the way to idle because the twist grip would go to it's idle position. I twisted back and forth and finally noticed the recoil bolt had come a bit loose and the recoil spun, causing a bolt on the timing plate to hit it. Glad that's all it was, cost me $0, just a dumb glitch. Thanks again
 
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