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10 hp johnson

You probably did not get the brass coupler connected properly. Go back and check that, the rod needs to be seated fully before the bolt can be put in.
 
Look for a small plastic lock just above the manual starter pulley that prevents the manual starter from being pulled.
 
The reason for 9.9's is many northern MN lakes had to be under 10hp
I really believe it started right here. Don't mess up the threads on that shift coupling. Make sure you are lined up.
 
timguy said:
Really, but most sales are in USA?
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Don't know where they have the largest sales volume, but my understanding behind the engineering of a 9.9hp motor is that it was to clear the legal hurdle of the boat licensing requirement in Europe. (Not sure if there are States in the US that require the same licensing?)

Not that it matters, but always enjoying shooting the $#!t, and since the topic has been brought up in the thread, we can't be accused of veering or hijacking.... :D
 
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The 9.9 makes a great 15, just change the carby and the ramp on the stator that advances the carby butterfly. Put your 10 hp cover on and she goes like a "raped ape". I'VE DONE PLENTY.......here in Northern Minnesota. Numbers still show a 9.9 "10".
 
timguy said:
The 9.9 makes a great 15, just change the carby and the ramp on the stator that advances the carby butterfly. Put your 10 hp cover on and she goes like a "raped ape". I'VE DONE PLENTY.......here in Northern Minnesota. Numbers still show a 9.9 "10".
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You don't need to change the ramp on the stator for the 9.9/15 hp conversion they are the same. In 1974 when the 9.9 hp came out, the U.S. was the largest outboard market. So the 9.9 designation was because a lot of the states had hp limitations on there lakes and the designation is on the hood only. The model #s start with either E10 or J10 because they are actually 10 hp motors.
 
timguy said:
The 9.9 makes a great 15, just change the carby and the ramp on the stator that advances the carby butterfly. Put your 10 hp cover on and she goes like a "raped ape". I'VE DONE PLENTY.......here in Northern Minnesota. Numbers still show a 9.9 "10".
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Oh yeah.... my 79 has a 15 carb on it (I got it already converted) and it's night and day with the 9.9.
I have a 9'6" inflatable that is rated for 10hp max, and this motor is way too much for the boat to handle; so since I also need more room for my diving gear, I decided to buy a 12'5" (made a killing on Ebay on one :)) and this one is rated for up to 25, I'll finally be able to use the 9.9 converted to 15 full throttle safely!

Thanks for the info Scott.... I knew it had to do with circumventing "some" HP regulation, be it here or in Europe. Or both. :)
 
Yeah, thanks Scott. I noticed a slight difference in the ramp on some years, but I've done carbys without ramps on some without a noticeable difference. I have also sold/traded 9.9 cowlings to primarily guides........and my customers that fish in waters with restricted horsepowers. Its obvious, but not to most game wardens/park rangers.
 
Yes the cam has changed designs over the years. But as long as the carb is the same style as the one you are taking off. You should only need to swap the arm on the carb itself from the 9.9 to the 15 hp carb and should be good to go.
 
flyingscott said:
Yes the cam has changed designs over the years. But as long as the carb is the same style as the one you are taking off. You should only need to swap the arm on the carb itself from the 9.9 to the 15 hp carb and should be good to go.
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Sorry, I don't follow (and I want to learn). What is the "arm" you are mentioning here?
 
timguy said:
The 9.9 makes a great 15, just change the carby and the ramp on the stator that advances the carby butterfly. Put your 10 hp cover on and she goes like a "raped ape". I'VE DONE PLENTY.......here in Northern Minnesota. Numbers still show a 9.9 "10".
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I like this guy
 
Jupiter Dinghy said:
Sorry, I don't follow (and I want to learn). What is the "arm" you are mentioning here?
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The plastic arm I am talking about is the the one that holds the roller against the cam. . Some arms are adjustable and some are not and some cams are adjustable and some are not. That is why the pair of them have to stay together or be replaced with the same part. The first metal cams were adjustable with 2 bolts. The second version is a plastic cam that is not adjustable and the arm is. The 3rd version of the cam has an adjustment screw on if and the arm is not adjustable. That's why it is important to keep those together. And the cam and roller arm are the same part #s between similar year 9.9/15 motors.
 
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flyingscott said:
The plastic arm I am talking about is the the one that holds the roller against the cam. . Some arms are adjustable and some are not and some cams are adjustable and some are not. That is why the pair of them have to stay together or be replaced with the same part. The first metal cams were adjustable with 2 bolts. The second version is a plastic cam that is not adjustable and the arm is. The 3rd version of the cam has an adjustment screw on if and the arm is not adjustable. That's why it is important to keep those together. And the cam and roller arm are the same part #s between similar year 9.9/15 motors.
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Thank you so much, great info!
 
On a typical conversion, my goal is to have the carb butterfly parallel with the cylinders or in other words flat in line with the carb bore, when stator plate has rotated to max timing advance. This can be achieved by adjusting the parts Scott mentioned. Full timing advance can also be tweaked a bit. Thats another discussion, but not a big difference in many applications. Props, altitude, mixing ratio, oil type, fuel octane, are all important considerations.
 
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Thanks Timguy, to be clear, by "full timing advance" you refer to full throttle correct? When the butterfly should be flat (wide open)?

BTW, Plugg28, did you ever fix the "start-in-gear" condition? :)
 
Full timing advance cannot be tweaked on them without a grinder. The timing stop is cast into the block and is preset at the factory. A link and sync needs to be done anytime the carbs are moved or replaced. This will time the carb and stator together.
 
flyingscott said:
Full timing advance cannot be tweaked on them without a grinder. The timing stop is cast into the block and is preset at the factory. A link and sync needs to be done anytime the carbs are moved or replaced. This will time the carb and stator together.
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So here's a question on this subject:
On my 76, I couldn't get the idle set right. Even with the side knob pushed all the way in, it would be too low and eventually stall.
I checked the linkage, and it was right according to the manual which states that the butterfly should barely start to move as the roller makes contact with the stator cam.
My thought was the roller had worn so I slid a piece of fuel line that fits right onto the roller real tight, and now I can fix my idle just fine with the side knob, and the link/sync seems to be ok still. What am I missing?
What are the symptoms of a link/sync out of whack?
 
Jupiter Dinghy said:
So here's a question on this subject:
On my 76, I couldn't get the idle set right. Even with the side knob pushed all the way in, it would be too low and eventually stall.
I checked the linkage, and it was right according to the manual which states that the butterfly should barely start to move as the roller makes contact with the stator cam.
My thought was the roller had worn so I slid a piece of fuel line that fits right onto the roller real tight, and now I can fix my idle just fine with the side knob, and the link/sync seems to be ok still. What am I missing?
What are the symptoms of a link/sync out of whack?
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That's because those idle knobs never work right. If you go to http://www.leeroysramblings.com/OMC_info/OMCinfo.htm he tells you how to modify them so they actually work.
 
Not sure about your roller, it shouldn't wear that much. The idle knob and related components on port side can wear so they dont stop throttle where they should. For instance, the lock ring (clip) that holds the knob in will damage the groove in the knob and wont hold it tight against the lower cowling. I reface the knob's surface that rides against the cowling and cut a new groove for the lock ring with a hacksaw, grease it and then just like new.
Scott, I like grinders, shouldn't do alot of what I do, but manage to stay out of trouble most of the time. The Engineers are usually pretty good, but we have to cover for them sometimes.
 
I am saying you can't time them that way. There are no marks on the flywheel to see where your timing is. There is also no timing pointer they are designed to not have the timing messed with. Those motors are pretty high strung motors they have an RPM range from 5000-7000 rpm depending on the year. I have made that conversion more times than I can count never messed with the timing.
 
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All jonnyrude points type ignition use the point gap as the ignition timing. There is a special tool for adjusting the points using the two marks on the side of the armature plate. On the bottom of the flywheel are two marks 180 degrees out for checking with a timing light. The timing light is the most accurate but can be time consuming getting it correct. In general the ignition with the external coils you want to set the points closer to .022 and the ones with the coils under the flywheel set them at .020 those are field adjustments without the proper tools to get it perfect. Connect the timing light to any battery and point the light at the two marks on the side of the points plate (armature plate) and you should see the mark on the flywheel if the engine is running. You want the single mark on the flywheel to be in between the two marks on the plate.
 
kimcrwbr1 said:
All jonnyrude points type ignition use the point gap as the ignition timing. There is a special tool for adjusting the points using the two marks on the side of the armature plate. On the bottom of the flywheel are two marks 180 degrees out for checking with a timing light. The timing light is the most accurate but can be time consuming getting it correct. In general the ignition with the external coils you want to set the points closer to .022 and the ones with the coils under the flywheel set them at .020 those are field adjustments without the proper tools to get it perfect. Connect the timing light to any battery and point the light at the two marks on the side of the points plate (armature plate) and you should see the mark on the flywheel if the engine is running. You want the single mark on the flywheel to be in between the two marks on the plate.
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That is absolutely correct my mistake I was talking about the CDI models. That one is on me. But the WOT timing on them is still set at the factory the jig sets the points precisely.
 
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