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Johnson 90 2 stroke Need a Guru

T

Thatoldmercury

New member
Hi
Sorry for the long post
Johnson J9OTLETS
Boufht boat used awhile back
I posted this on another forum and everyone has been Great!
But i still cant find the issue.
Only Happens when i hit a boat wake ! Large or tiny one.
But instantly drops to 9 mph , it will throw you down into the boat if your not prepared for it !
Throttle will still be 3/4 to wide open depending on how fast i was going.
Switch off the motor, turn off the power sit for an hour , crank up instantly but will do only 9mph wide open.
Next trip problem fixed itself.
Has done this 8 different times after hitting a boat wake.
If i dont hit a boat wake it will run forever with no problem.
Took it to a river drove it up against a big log, tied it off.
Ran it in gear at 4,000 rpm.
Wiggle and pulled on every wire, tapped every module, jump on gas tank.
Never missed a beat.
Any ideas will be Greatly appreciated
 
Remove cowling.-----Hook up 2 timing lights.-----One on #1 cylinder and #3 cylinder.-------Do the test run over the wake.-----If spark is not lost , then repeat with #2 and #4 cylinder.----Post results of this testing.
 
I put my timing light in the boat when i took it to the river hoping i could recreate it and check that.
It does act like it has lost two cylinders or no timing advance but after sitting with it off they should come back ?
It does run perfect after trailering it back and forth.
Without touching anything it runs perfect the next trip, unless i hit another boats wake.
It should do it if i circle around and hit my own wake .
I am lake fishing.
I plan to go Monday do some fishing get close back to the ramp and hit my wake, then i will check it.
The only problem is it runs perfect at idle.
I may have to tie it off to the dock so i can run it in gear just fast enough that it is bogging down to test it.
It wont power load on the trailer at all when it doing this.
And it only does this when i hit a boat wake big or small.
If you have any ideas on what to test throw them out thier!
I have 30 years of boating and repairs and electrical repair.
And i have my fluke meter in the boat as well!
Thanks
 
Just install a new powerpack.----If that does not fix it try a new timer base.----Try stator.----Try coils.----Try wiring harness.-----Try new pins and sockets on electrical plug ins.-----Soon you will have it running like new.
 
Another motor would be cheaper lol
I have been down that rabbit hole a few times before !
It cheaper just to slow down and idle through a boat wake like i have been doing.
I just had to try it the other day since i was close to the ramp.
Glad i freshwater fish now, never go fishing again if i was saltwater fishing lol
 
Hi All
Went fishing today and at the end of my trip when i got close to the ramp i crossed my own boat wake 6 times at varying rpm and it did not go into limp mode the first time!
Has went into limp mode at least the last 8 trips when i crossed another boats wake at 20 to 35mph.
Only thing i have temporary fixed was the kill wire black yellow line coming from the key fell out and motor would not turn off, not sure if that was after my last trip or. Was a crimp connector that had 2 black wires crimped in the other end.
Previous owner had rewired the console and it all looks sad.
All my stuff has came in so i plan on rewiring it better hopefully!
All my connections will be soldered and have shrink tubing with sealent.
I am getting rid of the wire nuts and crimp connectors!
It also may have helped that i had 100 lbs of tools with me to check everyones reccomendations.
So i still dont know ?
Thanks for the help!
Pretty sure i will be back!
 
racerone said:
Remove cowling.-----Hook up 2 timing lights.-----One on #1 cylinder and #3 cylinder.-------Do the test run over the wake.-----If spark is not lost , then repeat with #2 and #4 cylinder.----Post results of this testing.
Click to expand...
I ran it after fishing and when i got close to the boat ramp i circled around crossing my own boat wake quite a few times and had No issues .
This is the first time in 8 straight trips it did not go into limp mode crossing a boat wake.
Only work i have done prior to this trip was .
Label and mark each cylinder on the flywheel at Tdc.
Bring timing light
And temp repair on a crimp splice because the black wire with yellow stripe coming from the key switch came out of the crimp connector that was attached to 2 black wires i am assuming were grounds will be tracing and labeling all wires for future trouble shooting .
Motor would not switch off with key.
I now have everything to redo the previous owners rewiring.
Too many butt splices and wiring nuts in the console for me!
I only do soldered connections on all connectors with shrink tubing myself.
So i dont know anything at this point.
Thanks for all the advice from Everyone
 
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