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.


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

Beats having a black motor! Love my E tec, 8 years now not a birp!

Little hone job / used piston / set of rings and you in business…(sarc)

Find a engine made today that runs for 25 years without costing you an arm and a leg.


The ENTER-NET Fisherman

You joke. But, I enjoy playing with these things. HenryO hull will definitely get new power. Love that hull.

The old Johnson 2moker may get played with just for fun. Never tried to do a piston and rings.

Questions about a replacement piston. I see Sierra piston kits for about $100 (piston, rings, wrist pin, and clips). Maybe could find a used donor. Is it possible to remove carbs and reed valve assembly and get at the front of the connecting rod bearing? If so, I may try a hone and new piston. Cylinder is scored some. But , I’ve broken down motors that looked nearly as bad and went back together and ran a long time. Held 50 psi like she was, if a little work got her 90 or better… Would never sell without disclosing full history. Shoot, history is literally on the internet

And, I have a 14’ Bentz with the same transom bolt pattern. And, I’ve seen several 14s carrying old Merc and OMC 90s. Could be fun.

Hey, hold my beer… Watch this…:smiley:

Will have to see if I can break any time free to play.


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

I enjoy your posts.

I believe you can separate the crankcase from the block( if you are a wrench freak), but , it could/would be a waste of time. I’ve never done it…seen it done …and there’s this:
https://forums.iboats.com/forum/engine-repair-and-maintenance/mercury-mariner-outboards/341319-replacing-johnson-outboard-piston

The problem is the more 25 year old bolts you remove…the more chance of breaking them. Depends on what you want when you get done and what the rest of the mot

“Beats having a black motor”. “Got 8-years on my etec”. Eight whole years? I got underwear older than that! 23-years on my 30 hp tiller Merc with no issues. Poor mouthing abounds but my Seasoned personal experience tells me otherwise.

If I could post pictures I would post one of the 7 v6 Mercs that have holes in the block hanging on stands behind my barn. Altho I have a running 2.4 200 84 model that still runs great

Go to any old country area or mountain area where money is an issue every motor around is a old smoker. I had a Johnson 70 that was bored to a 90 by a airplane mechanic and his buddy who was a machinest. Two strokes are great.

Well… She’s done.
Carbs came off easily as they got cleaned every few years. Reed assembly came off easily = surprise! Reeds looked great. Outer crankcase bolts came easily = more surprised. 4 of the 6 Allen head crankcase bolts came out clean = (beginning to hope I have something to play with)… Then, the two lower Allen head bolts seized hard. Could pull the power head and put some heat on them… But, that’s more than I’m willing to put in to her. Parting her out. Everything worked except that the new cylinder. Anyone need parts for a mid 90s OMC/Bombardier?


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

Sorry to hear the motor has reached the end of it’s useful life for you. What horsepower is it?

1995 Johnson 88spl. No VRO. Does have trim/tilt. The 88 special is literally a 90 with slightly lower amperage output (6 amps instead of 9, I think).


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

i sure wish that was a 1995 ocean runner. i’d buy the whole setup. im looking for a power pack


_____________________________________________________ Proline 201WA Aloha 24ft pontoon (LooneyToon) Old Town stern with 7.5 johnson

Here’s a mystery.

That motor on that hull has always done 30-31 mph WOT. I always thought a 90hp should push her better than that but, she ran smoothly, idled nicely, and generally behaved herself if she had clean carbs. Slightly disappointing fuel economy but she’s a 25yr old 2-smoker.

Here’s the mystery. The last trip, after fishing a spot, 'had a little difficulty getting her to start. She’d spin and fire, stumble, and die. She did it maybe 10 times. Then, got enough start-up lever in her and she fired up and ran. Figuring low speed jets were dirty, I ran her WOT back to the trailer. 31mph.

Second part, on the hose in the driveway, I did a little tidying up of the timing linkage and she went back to purring at idle. I figured since she was warmed up, I do a quick compression test and that was my first evidence of a bad cylinder.

Note that the intake side of the piston face has more carbon build up and there is carbon in and on the dents left by the piece of ring bouncing around in the cylinder. Same is true on the under side of the head.

Question: have I been running on a very weak cylinder for a long time? Curiosity is getting the better of me. I think I’m going to pull the power head and see if I can’t get those last two crank case bolts to free up. If I can, will get a piston kit and put her back together. I have no expectation that she’ll hold together for very long. But, I’m getting ready to have to buy a new motor. Have been thinking a 115 or larger. But, if a 90 4 stroke will push her near 40mph, I’ll save some transom weight and go back with another 90? Decisions… decisions…


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

If the block and crank are good…
http://smellofdeath.com/lloydy/piston_diag_guide.htm


The ENTER-NET Fisherman

I got enough stool to work on around here, but, I gots to know why that piston ate the ring.

The cylinder got hot due to the ring failure or some other cause?

If you get apart, I’d like to know if the locating pin failed…or just old rings.

Show me a four stroke that will run with damage like that.


The ENTER-NET Fisherman

Well, here’s the problem child. I am absolutely amazed this motor was running reasonably well/smoothly with this in one of the holes. I guess 50 psi compression is more than zero. But, hard to believe.

Obviously, spit out the entire top ring and took a few chunks of the piston with it. Can not believe the entire ring made in into the combustion chamber and got spit out. Didn’t get back down into the crank case = would think that would have destroyed everything quickly.

I broke three bolts getting her apart. If I can either get those out or helli-coil them I’ll order a piston kit, hone the cylinder a little, and throw all this back together. See if she lasts longer than 5 minutes.


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

that’s unreal, thanks for the pictures! Good luck on the rebuild hope it runs another 24 years!

You mention that you thought the boat/motor was slow but OK:

"That motor on that hull has always done 30-31 mph WOT. I always thought a 90hp should push her better than that but, she ran smoothly, idled nicely, and generally behaved herself if she had clean carbs.

I wonder if it was propped right? Just a thought.

https://forums.iboats.com/forum/engine-repair-and-maintenance/johnson-evinrude-outboards/101539-96-johnson-115-piston-head-damage-pics

The picture of the piston that you have appears that the ring locating pin broke loose. The lugging may explain the heat build up. Just a thought. Good luck with the rebuild. Beeswax and heat are our friends.


The ENTER-NET Fisherman

mdaddy,

I’ve forgotten the numbers, but, I ran a 15 3/4" x 17" prop on her for a long time and she was right below the bottom of the prescribed range for WOT RPMs. About a year ago, I dropped to a 16" pitch prop and it made almost no difference. RPMs went up as expected, but, speed stayed just about the same. Fuel burn stayed about the same. So, I think that means that even if she was a little below the prescribed WOT range, she was doing OK with the 17" pitch.

Regarding the ring locator pin, it is still there and in pretty good shape. It is just around the side of the piston in that pic where you cannot see it. The amount of carbon built up in that top ring lane makes me think this old girl spit that ring out a long time ago. Much of that lane is almost completely full. And, it is hard as a rock. Its been in there baking in place for a while.

Had three bolts that I’d twisted the heads of off and could not get out of the block. After heating gently and shooting with PB Blaster (don’t know if the stuff works or not - but, gave it a try) and leaving it for two days. Then, came back, more heat, vise grips as tight as I could get them and got two of the studs out. The third would not budge and I was torquing on it so hard I was a little afraid of ripping a chunk of aluminum out. So, cut it off about 1/8" tall. Filed it flat. Put a sharp felt tip dot in what I thought was the center. Center punched the dot several times to give good dimple and started drilling with a very small drill bit. Stepped up right through the bit set until I started to see the hint of threads in the wall of the hole. Ran a tap through the hole and it cleaned out nicely. I’ve tried to do that trick dozens of times over the years. This is the first time I did not end up having to over drill and heli-coil or re-tap it. Very Very lucky.

So, ordering a piston kit and a variety of gaskets. When the parts arrive, I’ll put her back together.

Once I get the piston in, I’ll hook a drill mo

If you got skills a rebuild should last as long as the original or longer. 2 smokes are built to be rebuilt. I’m sure some other things will take a dive since they are 25 years old