Notices
The Boating Forum

Johnson 90hp (J90PLEEB) issues

Old 08-22-2020, 06:29 PM
  #81  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Originally Posted by cfauvel View Post
can you cancel your stator and flywheel order...no need to throw many at it if THAT isn't the problem?

it is the 4 little bullet things ...all they are are springs on one side and a solid piece of brass on the other.
Just checked and both have already been shipped. Well the flywheel has a tracking number assigned.

Just ordered these.
https://www.wholesalemarine.com/terminal-extender.html

Likes:
Old 08-26-2020, 06:44 PM
  #82  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

For anyone following along with this thread.

1) Measured the stator resistance and DVA voltage - in spec
2) Measured the DVA output from the power pack to the primary coil wires - in spec
3) Measured the sensor DC voltage - in spec

I then set the timing with the johnnyrude easy timer Analyzer.
1) Disconnected the throttle cable
2) Adjusted each carb to be fully closed
3) Using a depth gauge I was able to verify that the pointer was correct pointing to TDC
4) Rotated to 4deg ATDC and set the idle stop to where the CYL light turned off.
5) Moved the arm so the throttle was wide open
6) Rotated (clockwise) until 20deg BTDC, set the high stop to where the CYL light turned off
7) Tighten the idle screw that locks the tabs
8) Moved the arm back and tighten the screw

The rectifier gell side looks a bit worn (see photos) and the yellow wires look discolored.







Last edited by TopherMichael; 08-27-2020 at 11:20 AM.
Old 08-27-2020, 12:19 PM
  #83  
Admirals Club Admiral's Club Member
 
Dacman's Avatar
 
Join Date: Oct 2014
Location: Summerville SC
Posts: 9,302
Received 1,026 Likes on 776 Posts
Default

I thought those timing tabs placement looked questionable when I saw them. Someone messed with them.
How does it run now?
I would replace that voltage regulator, looks melted and plug over heating.
Old 08-27-2020, 12:22 PM
  #84  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Originally Posted by Dacman View Post
I thought those timing tabs placement looked questionable when I saw them. Someone messed with them.
How does it run now?
I would replace that voltage regulator, looks melted and plug over heating.
The sky opened up, waiting for the rain to stop before I can start her up.

Still planning on pulling the flywheel to inspect.

Will order a new regulator... pricy item.
Old 08-27-2020, 12:25 PM
  #85  
Admirals Club Admiral's Club Member
 
Dacman's Avatar
 
Join Date: Oct 2014
Location: Summerville SC
Posts: 9,302
Received 1,026 Likes on 776 Posts
Default

If you replace the rectifier or regulator, get a spare gasket and don’t use gasket dressing on the seal, I learned the hard way.
It is water cooled .
Old 08-27-2020, 12:34 PM
  #86  
Admirals Club Admiral's Club Member
 
Dacman's Avatar
 
Join Date: Oct 2014
Location: Summerville SC
Posts: 9,302
Received 1,026 Likes on 776 Posts
Default

I used the aftermarket for mine years ago, I think it was Sierra through , not CDI.
I would recommend going OMC . Mine works fine but the footprint was smaller and not a many cooling vanes like the OMC.
Rhe problem with the footprint was not as much rubber sealing surface and I had a leak right off when I used sealer. It squished out the rubber gasket.
Go dry and clean.
The failing symptoms on mine were erratic voltage charging levels and the tach would drop out and jump around.
Old 08-27-2020, 12:47 PM
  #87  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Originally Posted by Dacman View Post
I used the aftermarket for mine years ago, I think it was Sierra through , not CDI.
I would recommend going OMC . Mine works fine but the footprint was smaller and not a many cooling vanes like the OMC.
Rhe problem with the footprint was not as much rubber sealing surface and I had a leak right off when I used sealer. It squished out the rubber gasket.
Go dry and clean.
The failing symptoms on mine were erratic voltage charging levels and the tach would drop out and jump around.
I ordered the CDI version. Did not know that it was water cooled, so thanks for that info.

I think this one is working good, but has real physical signs of being worn and it appears to be original.

The other test I want to do is swap top/bottom carbs to see if the issue follows.

Old 08-27-2020, 01:00 PM
  #88  
Senior Member
 
Join Date: Oct 2019
Posts: 395
Received 154 Likes on 89 Posts
Default

From what I understand a shorted rectifier could cause those yellow wires to burn.
Old 08-27-2020, 01:06 PM
  #89  
Senior Member
 
Join Date: Oct 2004
Location: RI
Posts: 1,918
Received 411 Likes on 254 Posts
Default

I had the same issue as Dacman with the reg/rec gasket - definitely do not use any sealant on it, install it dry.

Will be interested to see your progress as I am dealing with similar issues. My timing tabs have been "messed with" as well and are set seemingly strangely like yours were.

Thanks for the updates.

Old 08-27-2020, 01:30 PM
  #90  
Admirals Club Admiral's Club Member
 
Dacman's Avatar
 
Join Date: Oct 2014
Location: Summerville SC
Posts: 9,302
Received 1,026 Likes on 776 Posts
Default

Originally Posted by TopherMichael View Post
I ordered the CDI version. Did not know that it was water cooled, so thanks for that info.

I think this one is working good, but has real physical signs of being worn and it appears to be original.

The other test I want to do is swap top/bottom carbs to see if the issue follows.
You could probably rent out that timing tool here. I have wanted one just to check mine , but it runs really good , so I haven’t made the purchase.
Likes:
Old 08-27-2020, 04:24 PM
  #91  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Quick video of a spark gap test. As you can see all cylinders seem to have a good spark. I have not pulled the flywheel yet to visually inspect the flywheel and stator. So far all ohm and voltages measurements are in spec, however, the motor still does not change RPM's when I pull the starboard bottom plug. If it is clear out tomorrow, I plan on swapping the top and bottom carbs.

Old 08-27-2020, 04:25 PM
  #92  
Senior Member
 
Join Date: Oct 2004
Location: RI
Posts: 1,918
Received 411 Likes on 254 Posts
Default

It seems you're getting closer to it NOT being an electrical problem...
Old 08-28-2020, 08:56 AM
  #93  
Senior Member
 
Join Date: Jul 2016
Location: Perth WA
Posts: 2,973
Received 642 Likes on 404 Posts
Default

did you end up thoroughly inspecting the reeds ? .
Old 08-28-2020, 09:01 AM
  #94  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Originally Posted by 1breakinit View Post
did you end up thoroughly inspecting the reeds ? .
Yes, zero light shining through.





Old 08-28-2020, 11:46 AM
  #95  
Senior Member
 
Join Date: Jul 2016
Location: Perth WA
Posts: 2,973
Received 642 Likes on 404 Posts
Default

all the gaskets i guess were intact ?.
which brings me to thinking you may have an air leak into the crankcase

when the motor is running , use some carb cleaner and spray around the cases , etc.
you will be listening for any changes in RPM or engine sound ., an air leak can do as you described .
Old 08-28-2020, 11:51 AM
  #96  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Originally Posted by 1breakinit View Post
all the gaskets i guess were intact ?.

when the motor is running , use some carb cleaner and spray around the cases , etc , you will be listening for any changes in RPM or engine sound ., an air leak can do as you described .
All carb gaskets are new. I do have a new gasket to replace the one in the photo.

I will try using carb cleaner to detect air leakage.
Old 08-28-2020, 02:41 PM
  #97  
Admirals Club Admiral's Club Member
 
Dacman's Avatar
 
Join Date: Oct 2014
Location: Summerville SC
Posts: 9,302
Received 1,026 Likes on 776 Posts
Default

Originally Posted by TopherMichael View Post
Quick video of a spark gap test. As you can see all cylinders seem to have a good spark. I have not pulled the flywheel yet to visually inspect the flywheel and stator. So far all ohm and voltages measurements are in spec, however, the motor still does not change RPM's when I pull the starboard bottom plug. If it is clear out tomorrow, I plan on swapping the top and bottom carbs.

https://youtu.be/uWKkYs2bkOQ
Spark looks great to me , not sure I would bother pulling the fly wheel.
Maybe you’re just stuck on trying to eliminate a non issue with the one cylinder not making a difference at idle?
At operating speeds with a load it should make a difference , but at idle with a 4 cylinder , It might not.

Maybe disconnect the two wires on that side at idle , hear it stumble, then reconnect the suspected cylinder and listen for pickup .

Im probably wrong , but i think you’re chasing a non issue. 4 cylinders can idle fine on 3.

Just a idea.
Old 08-28-2020, 02:42 PM
  #98  
Admirals Club Admiral's Club Member
 
Dacman's Avatar
 
Join Date: Oct 2014
Location: Summerville SC
Posts: 9,302
Received 1,026 Likes on 776 Posts
Default

You’ve got the timing set which was wrong. Maybe time for a sea trial at load.
Try the plug wire removal test on the water with a load powering up.
Old 08-28-2020, 03:22 PM
  #99  
Senior Member
Thread Starter
 
Join Date: Sep 2019
Location: York, ME
Posts: 118
Received 13 Likes on 9 Posts
Default

Switched carbs and the issues didn’t follow. Not a carb issue

So I tried spraying carb cleaner between these 2 areas and the revs jumped.



Old 08-28-2020, 03:28 PM
  #100  
Senior Member
 
Join Date: Jul 2016
Location: Perth WA
Posts: 2,973
Received 642 Likes on 404 Posts
Default

use paint and draw an arrow directly to where the spray made the revs jump .

seems you have and air leak !, just a matter of finding / pin pointing the exact source..

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.