Replace 1976 power pack with 1996 power pack

dreese2005

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I have a 1976 Johnson 85 V4 Seahorse that has no fire on Cylinder#3 I have replaced the coil with a known good coil. still no fire. So at this point based on deductions I am guessing that the power pack is bad. I have a known good power pack from a 1996 V4 112 HP that I would like to use I can and have crossed referenced the wires and have figured out all but a few. here is what I know and what I need help with.

on the 76 there are 4 wires coming from under the flywheel 2 black with white tracers and two white with black tracers they go to terminal marked sensor 1 and sensor 2

on the 96 there are 5 wires green, pink, white, purple and blue I need to know how these wires connect to the black/white white/black wires and what the 5th wire is for?

any help would be greatly appreciated.
 

dreese2005

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Could you please explain the reason that it wouldn't work? I believe it would if I knew how to cross splice the wires. I don't understand why it wouldn't work. They are essentially the same motor correct?
 

flyingscott

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The motors are themselves are similar but the ignitions aren't. There is a 20 year difference in those ignitions systems. I believe the 96 will have the quick start and S.L.O.W systems which are part of the powerpack your 76 model has neither of those. The stators themselves I believe are also different.
 

dreese2005

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So heres what I did. I installed the magneto (which had the 5 wire plug) and the power pack from the 1996 112hp v4 onto the 1976 85hp it now fires on all 4 cylinders however it is idling way to high. I do not have a tach so Im not sure how high. I would guess 1800rpm or better I cleaned the carbs ( took them apart and soaked in Chem dip then cleaned with carb cleaner) both butterflies are completely closed. and the spark advance is completely against the stop. the carbs are fixed jet carbs so I am not sure of any way to reduce the idle at this point. there are no air leaks of any kind anywhere. Is this due to the power pack replacement? is there another adjustment I am missing? I do not currently have the manual for this motor. I need to get this figured out before this weekends tournament. Any advise from anyone would be of great help to reduce the idle speed. I do know that with the old power pack, when it did fire on all cylinders it also revved way high so I am assuming this is something the previous owner did to compensate for the dead cylinder.
 

dreese2005

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Sorry, Also the idle screw is out (away from the stop) and the manual choke is completely off ( not in the on or auto position)

Thanks
 

Strangeleak

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Jan 20, 2017
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Considering you're swapping parts on such a large year gap this is a complete shot in the dark.

Theory #1: The '96 112hp doesn't appear to have the Quickstart feature according to CDI Electronics Troubleshooting guide. Could be wrong though. If so, Quickstart would advance the timing until the head temperature reaches 96?F. And if your engine has no such sensor, then the power pack would never drop out of Quickstart. It looks like a white/black wire controls this on the temp sensor. If you have a spare white/black from the powerpack, try grounding it.

Theory #2: Did you swap over the stator as well? Is that what you meant by magneto? For this to work properly and achieve correct timing you would probably have to swap everything from the 112 to the 85. Powerpack, stator, timer base(trigger), and flywheel. Rectifier/regulators are the same. The engine idle is set by the timer base position in relation to the stator/flywheel triggering magnet. If you didn't swap the everything over, then the trigger positions won't line up. According to the attached PDF, the 1987 and older V4 crossflows trigger locations are at roughly 6 and 12 o'clock. The 1988 and newer V4 crossflows are at 3 and 9 o'clock. Even if you do swap it all over, the starter from the 85 may not lline up with the teeth from the 112 or the tooth count may be different between the flywheels.

If you didn't swap it all over, consider this. The base timing degrees on a 1976 85hp and a 1996 112hp are probably not the same. If your idle is too high then your timing is probably too far advanced. Try rotating the timer base clockwise to retard the timing.

If the timing can't be retarded enough to bring your idle down then it sounds like the timer base from the 112hp does not have sufficient range of motion to work on the 85hp.
 

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dreese2005

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Strangeleak, Thank you this was Very helpful. When I said Magneto I was speaking of the Timing Trigger. I did not swap the stator and flywheel. The stator is already off of the 96 ready to go on the 76 ( this was my next move) I did not however, consider the flywheel. I believe the 96 flywheel will fit the 76 and I know the teeth line up as I already had the starter from the 76 on the 96 in the past. So if the holes are the same size it should work perfectly. I will make these two changes this afternoon and report back. This is very encouraging and exciting stuff.
 

Strangeleak

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Make sure to measure the flywheel "channel" between the inner/outer magnets before slapping it on the '76. If the '96 is much wider it won't generate the needed magnetic field. If its narrower it will contact, and likely damage, the stator upon installation.
 

dreese2005

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Strangeleak,

We have a winner.. power pack, timing trigger, stator and flywheel from 96 are installed on 76... solved the high idle problem... now to set the timing, do a link and sync and we are headed to the ramp to check it all out... Thanks for your help.. This has turned into a bit of a franken-motor but it is nice to know that johnson kept so many things basically the same for so long...I was quite certain by looking at the whole scenario that there would be a way to make it work. it is amazing how many parts from the 96 will interchange with ther 76... maybe a newer version but the same parts..., Again, Thanks for your help... I will keep you posted as to how the "on the water" test goes.
 

Strangeleak

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Glad it worked out! How'd the tourny go?

Just curious, was the stator the "keystone" or was the flywheel different? Magnet positions in relation to #1 Cyl TDC? Might be useful information for someone in the future who wants to do the same thing you did.

Would be a nice contribution for you to explain what re-wiring you had to do, any modifications made, pictures, etc.
 
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