never buying another Johnson


Stupid motor only lasted 25 yrs. /sarc

Is piston supposed to look like this?

Appears to have eaten a ring. Inside of head looks like tip of piston.

Old girl ran like a top for a long time. Never failed to get me home. Not one time.

Guess it's time to start researching repower options.


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17' Henry O Hornet w/ Johnson 88 spl
26' Palmer Scott project hull
14' Bentz-Craft w/ Yamaha 25
Replies

There's an art to working on junk. I like your dedication and tenacity. They be in short supply in most cases.

Now, what is this???:




Not sure what the round shape is. The ring locator pin is intact. Only guess, is a purely random shape produced while the ring was being spit out. It appears to be made of the same material as the rest of the piston body. Here's a pic of the intact ring locator pin.




The picture looks like a locating pin stuck to the piston... Or cracked up through. Either way, find a good machine shop to check the block and crank since it's apart.(Nice to have other eyes depending on price and you having micrometers)




The ENTER-NET FishermanOriginally posted by mdaddy


I'm livin on the edge. No micrometers here. Everything else on this old girl is 25 years old and she just doesn't warrant any significant investment. I'm gonna spend about $180 on parts and throw her back together. See what happens.

I'm going to be optimistic as say she runs another couple of years. I'll try to remember to video her first start. Could be comical.


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17' Henry O Hornet w/ Johnson 88 spl
26' Palmer Scott project hull
14' Bentz-Craft w/ Yamaha 25
Last edited by PalmerScott
Good for you. That motor laughs at micrometers.

Much simpler motor that did what it was posed to do...start and run...and doesn't need 20 sensors to do it.


The ENTER-NET Fisherman
Don't know when I'll get to it... may be this weekend. But, ...... parts!




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17' Henry O Hornet w/ Johnson 88 spl
26' Palmer Scott project hull
14' Bentz-Craft w/ Yamaha 25
Progress.



Piston to con rod small end done. Needle bearings are a pita. You have to nest the bearings in the end of the con rod. Then, slide wrist pin into piston and through bearings with out having them collapse....which they do. Manual says buy this tool which is just a little plug the width of con rod that sits inside bearings until the wrist pin pushes through. Had a tapered candle. Mic'd the wrist pin and cut a 1/2" length of candle. Perfect. Easy on aluminum piston and held bearings in place.

Install rings. Slather with 2 cycle oil.
Slide into cylinder and mate to crank.

Lightly tightened con rod end cap and spun crank several revolutions. Everything was smooth.

In the am, torque con rod end cap. Close case. Reinstall all the 12million things I removed.


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17' Henry O Hornet w/ Johnson 88 spl
26' Palmer Scott project hull
14' Bentz-Craft w/ Yamaha 25
people rarely understand the NEED to do a carbon treatment on their motor.
Based on the pictures, if I were betting, I would bet that you got carbon build up behind the rings, ring sticks out just bit farther than it should, and catches the edge of the port on the way down. The broken piece of ring ends up banging around on top of the piston until it gets spit out the exhaust port.
Seen it happen over and over again.
Morale of the story...
the inside needs to be clean as well as the outside

PS
if you ever do another build like this, you can order caged needle bearings for most motors, and they are only a few dollars more than loose bearings, and vaseline does a really good job of holding the loose bearing in place while doing your assembly.


www.teamcharlestonmarine.com
IF I RESPOND IN ALL CAPS, ITS NOT ON PURPOSE, AND I AM NOT YELLING
Get it man. Those needle bearings will make you swear.

I rebuilt a Merc 125 that had those as well as 6 different ring compressors. My girlfriend at the time was trying to help me put the assembled crank back in the block while taking off each ring compressor...and told me where I could put the whole motor. She never did get a boat ride.

" Mic'd the wrist pin and cut a 1/2" length of candle. Perfect." The only thing mic'd was a candle...classic. My long lost twin.
Won't be long now.


The ENTER-NET Fisherman


The ENTER-NET Fisherman
Last edited by mdaddy
Quick clarification on two points.

First, I hoped that it might be possible to split the crankcase with out removing the power head from the exhaust adapter and it was suggested that it might be possible. It may be possible on other motors, but, on a 1995 88spl (or 90, or 112, or 115), there are two bolts going up through the bottom crank case head assembly (bottom end bearing cover) through the cover and into a ring that goes around the crank shaft. You cannot open the crankcase without removing those two bolts. No way to get to those to bolts without removing the block from the exhaust adapter.


Second, I cannot lie. I did not 'mic' the wrist pin. I used a vernier caliper which I like because it makes me look like a Wizard when people see me use it. Invariably, "how do you read that"? (Knew how to use a slide rule for about a month, then never picked one up again. Those guys are Wizards.)



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17' Henry O Hornet w/ Johnson 88 spl
26' Palmer Scott project hull
14' Bentz-Craft w/ Yamaha 25
Slide rule?! They quit making those in the late 70’s. smile. Talk about old school. I wonder how many are out there that could still read one?
slide rule...
okay guys im 52 and my dad used one when i was kid
and he is 87 now
I am sure he still has one somewhere.
I will stick with my cell phone


www.teamcharlestonmarine.com
IF I RESPOND IN ALL CAPS, ITS NOT ON PURPOSE, AND I AM NOT YELLING


www.teamcharlestonmarine.com
IF I RESPOND IN ALL CAPS, ITS NOT ON PURPOSE, AND I AM NOT YELLING
Last edited by chris V
got one i used in tech school and work calculating electrical loads and the such ;( it still works but i don't anymore )


George McDonald
US Navy Seabees,Retired,
MAD, Charleston Chapter
[http://www.militaryappreciationday.org


When you see "Old Glory" waving in the breeze, know that it is the dying breaths of our fallen hero's that makes it wave.
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