Johnson 15hp 2-stroke high pitched noise then stopped working

[freddyray21]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

there is no gasket between the crankcase halves. Never was one. Just use the proper sealer when you put it back together. I think perhaps you may have broken a rod or rod bearings and that is why it hung up when turning. It would also explain the slop in the one piston. You will find out when you get the halve separated.

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

So how do I separate them? do I remove the dowell pin or just pry the heck out of it? I don't want to break anything. . . .

there is no gasket between the crankcase halves. Never was one. Just use the proper sealer when you put it back together. I think perhaps you may have broken a rod or rod bearings and that is why it hung up when turning. It would also explain the slop in the one piston. You will find out when you get the halve separated.

 

[AlTn]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

you may have to smack the crankshaft end with a rubber mallet to get the halves to separate..drive out the taper pins...the connecting rod screws are 5/32" allen head...keep all bearing shells, rods, wrist pins, pistons, etc. for each piston assembly separate from each other...no mixing them up....best to mark as you take apart as you know how "stuff" happens if you don't

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

I can't get this case apart and I'm afraid I'm going to damage it. HOw hard should I be hitting this and what side? The bottom side or the top where the shaft is sticking out?

 

[raczekp1]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

use piece of wood and tap in crankshaft end side to side and you could separate crankcase.
do this slowly, do not use any screwdriver or something

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

OKay, got it figured out

. . . and EUREKA! The bearing set on the top cylinder was destroyed.

Part #9 on this here diagram:

http://www.boats.net/images/diagrams/brp/IMAGES/393579/13.png


Now that I know the problem, is the solution as easy as just buying the bearings and replacing them? Or have I destroyed the crankshaft and it needs machined?

 

[AlTn]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

if you'll post some pics < with good lighting >....I'm sure some knowledgeable and experienced member will yield their opinion

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

What I mean is, should I be checking tolerances on the crankshaft journals and stuff like that? Do I need a micrometer?

Or should I just be eyeballing everything and seeing how much wiggle room there is in the crank assembly?

Also, what if there is too much wiggle (assuming any wiggle isn't too much)? Do I throw it away or can I get it machined and put a "cuff" around the journal?


Visually, everything looks fine regarding the pistons and rings. I'm assuming it would be wise to just get some new rings considering the compression was so low.

Other than that piston bearing, I can't find anything that even looks remotely bad about this engine. . . .

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

BTW - here are some pictures. The crankshaft was getting plenty of oil and doesn't "look" bad at all.

The top rod bearing was worn and exploded; not sure where all the little parts went; maybe they melted and blew all over the engine . . .I just don't know.

View attachment 106990

View attachment 106991

 

[AlTn]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

no working link to either attachment

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

Try these:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/283519_10150278724326730_689756729_7662683_4045994_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/281996_10150278724476730_689756729_7662685_7405408_n.jpg

 

[AlTn]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

can you disassemble it down to the crank and connecting rod crank end for that cylinder?..hard to tell much other than the crankshaft rod bearing disintegrated....what does the journal for that connecting rod look like?

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

Here are the pictures I think you want to see:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/215051_10150278920596730_689756729_7664942_557446_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/282025_10150278920806730_689756729_7664943_6451417_n.jpg

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/205955_10150278920981730_689756729_7664944_1305611_n.jpg



As you can see, the journal on the one end is rough (But not terrible. . .I dunno). The other one is mirror-smooth. The respective connecting rod on that side is also rough, as you can see in the picture.

Do I need a new rod and turn the crankshaft? A new rod is $170, afaik. That's insanely high.

Let me know what you guys think, especially if you think I can get away with just polishing it up. . . .

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

Okay, more pics (because if you post it, they will come!!):

First pic is of the bad rod, with one end polished:
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/229666_10150279225371730_689756729_7668476_2227386_n.jpg

Second Pic - both sides polished now

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc6/281735_10150279225511730_689756729_7668480_4945647_n.jpg

It looks good, it feels super smooth. . .until you compare the polished one with an original, unblemished one:

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/198689_10150279225686730_689756729_7668486_7777248_n.jpg

So do you think this is good enough or will there be too much friction, causing the bearing to be destroyed in a matter of hours -- or minutes!

Also, I'm assuming I should just get another set of rings as well. Let me know what you guys think!

 

[Mullerhawk]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

Do I need a new rod and turn the crankshaft? A new rod is $170, afaik. That's insanely high.

Let me know what you guys think, especially if you think I can get away with just polishing it up. . . .

Check this seller out from Singapore: http://stores.ebay.co.uk/ASCO-Quali...94077018&_sid=934127828&_trksid=p4634.c0.m322

He sells complete piston rods for about $30 and new pistons with rings for $25. Quite the difference!

 

[raczekp1]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

yes.i would buy this-2xconecting rod +2x piston kit.dont wait to loose

 

[AlTn]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

fwiw..checkout ebay item no. 290597401689

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

Thanks; unfortunately mine is a 83 and there were changes to the powerhead in 84. This is a different powerhead than mine.


I did find one on ebay w/o a compression test; maybe I'll just grab it up . . . .

 

[raczekp1]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

dont you want to have almost brand new powerhead-you did a lot of work while reasembling powerhead, so why dont put new pistons, rings and bearings.
if something will not work you will have a chance to sell parts on ebay and look for powerhead.
this item 290597401689 should work,but i think vertical idle shaft will need some rework

 

[catfighter]

Re: Johnson 15hp 2-stroke high pitched noise then stopped working

Don't forget the crankshaft needs machined as well.

I'm going to take it to the machine shop today and see what they say. . . .