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'97 150hp - Help Diagnosing Reverse Engagement Issue (torn down)

E

eyebrowski

New member
Johnson 150 Ocean Runner ([FONT=&quot]J150EXEUC)

[/FONT]Issue: Reverse engagement is temperamental either not shifting into gear and free revving or grinding then dropping in. Forward is never an issue and it does not pop out of gear.[FONT=&quot]
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I currently have the lower end off and the gears pulled. I suspected a dog clutch / reverse gear issue but after getting them out the gears look acceptable to me, can anyone confirm? I didn't see any shavings in the lube but it was not easy to see as I had an oil/water milkshake.

The shift rod was very stiff passing through the cover and o-rings. I broke the shift linkage at the block a couple seasons ago and I now suspect this was the cause. Could the stiff shift rod be causing the shift issues that I am having?

Thank you!
 

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Yes------Corrosion products build up in the cover and jam it.--------I do not believe these gearcases are as good as earlier ones.-----I am seeing early signs of gear tooth failure on forward gear.----More pictures of tooth surfaces would help diagnosis.----Clean shift rod cover bore.------Install seal kit.----Set shift rod height on installation.
 
Agree. The reverse gear is starting to round off. Not very good, but still adequate. You gotta make sure it's going into gear right away....not "grinding". Many operators think that they are doing good by "sliding" it into gear....NO!
 

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e as I had an oil/water milkshake.
Click to expand...
This is reason FWD gear and pinion look this way. No lubrication protection under load. A very good (express on very good) machinist and cut .008-.015 off REV dogs ramp and reuse with a new clutch dog. My old time machinist has since retired...was still racing BSA dirt bikes @71yearsold!!! He has cut several poster gears here and at other sites.
Charlie Southgate - The Music City MacGyver (nashvillescene.com)
Grease Monkey Magazine TV- Charlie Southgate Sr. - YouTube
 
Here are a couple more picture of the forward gear. I think I am going to freshen up the seals and put it back together to see if I can get some more life out of it. I put very few hours on it.
 

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In my opinion these new style gearcases are not standing up like the ones from the 1980's.----Gears suddenly fail on them.-----So run it till it goes -----BOOM---I guess.
 
Agreed. Nice crisp photos, very clean parts. They don't make stuff like they used too. Engineers now are making stuff to last "just long enough", and not engineering to last for a human lifetime......or even more. Put a little fine sawdust in it....like the old timers did with transmissions. Ha!
Seriously, you will likely hear a progressively louder harmonic before "she blows". Keep a keen ear and check gearcase lube often.
 
Only use a Hi-Po lube not a 80w/90 weight..OEM spec is for OMC Ultra-HPF lube. Clean up shift rod binding issues and reset to proper height.
 
I got everything resealed and put back together. It seems to be shifting ok on the bench.

Any tips on how to measure the shift rod height? Where is it measured from? Spec is 21-1/4” +/- 1/32”..seems a little tight to be using a tape measure.
 
A tape measure will do.------Measure from the case mounting surface.----Surface from surface to CENTER of the hole .----Gearcase in neutral.---I think offset on the rod faces forward.
 
Last edited:
racerone said:
A tape measure will do.------Measure from the case mounting surface.----Surface from surface to CENTER of the hole .----Gearcase in neutral.---I think offset on the rod faces forward.
Click to expand...
Yep, 21 1/4" from the mating surface of the LU, in natural, with the offset facing forward.

I used a piece of 3/4" x 3/4" light angle with a 2" long #8 machine screw to setup mine. With a tape measure I worried about measuring too short when I angled from the case mating surface up to the hole. I sort of copied the homemade tool used by Dangar Marine to make my jig: https://youtu.be/Ufy6W9EI1cg

KJ
 
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