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1995 Johnson 15 low compression in one cylinder

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Njm911

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I just got a 1995 Johnson 15 it has 60 pounds in the top cylinder it will start and run but won’t idle what should I try before I go and throw a lot of money at it what should I look for or try first
 
You have a blown head gasket.----Or damage to piston / rings / cylinder wall.-----Just 6 bolts to take the head off for a look see.
 
If there is bad glazing in the cylinder walls, then compression will go down too, if that is the case, you need hone your cylinders. If you try new head gasket, you need carefully remove all old gasket material from the sealing-surface, but dont damage the surface. Tighten the head-bolts evenly (someone can tell you the right order and right moment). Also tighten the spark-plugs carefully, not too much, but enough. When putting plugs back, i use first only my fingers, and then 1/4 turn more with tool.
 
Part of the block around the cylinder sleeve is gone dose this mean I need a new block or can it be fixed
 
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Post pictures.----I might be able to fix it depending on what I see.-----Not sure of what equipment / capability is in your workshop or local area.
 
Not sure how to do that myself.------Likely one of the icons ( third from the right ) above your reply.------I am better with wrench / trouble shooting than computer stuff.
 
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I like to take my picture first and then reduce its size to around 900k using something like lit photo. This creates a file that you can go back to once you write your thread. Click on "go advanced" and then above your thread click on the paperclip. Follow instructions. Click on "add files" then "choose file". This will allow you to your own files and photos so open them and choose the one you want. Your "choose file" screen will come back with your thread and then click on "upload". Your downsized photo should then appear at bottom of page after a short wait. Then click on "done". Like this! This is my boat in the Philippines, straight inboard direct drive 6.5 hp. She goes pretty good for a heavy wooden boat, probably 15 knots with 3 people.
Come on Racer, never to late to teach an old dog some new tricks. Just taught my 10 year old mutt how to "sneeze". PEOPLE can't even do a real sneeze on command. She keeps licking her nose until she gets the sneeze. Pretty neat.
 

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As I'm looking at the picture it looks like the cylinder on the right has some scoring. Is that the one with low compression?
 
Looks like it got really hot.---Aluminum separated from the cast iron liner.----Both cylinders look bad / separated in my humble opinion.-----Hurry and shop for another block.----E-bay is but one place.
 
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Your right, Racer, I see that.....your a much better man than me. That block is garbage, scrap, trash, a boatanchor. I probably have a good block, will check. How about Tim's Outboard....Hackensack MN. 218 682 2331....Mike or Dan. Tell 'em Tim sent ya. 4.9 * review.
 
Yes it really looks very bad, you need another block. Check also carefully the condition of your pistons and rings and all powerhead bearings because operating temperature is been too high.These engine works are best to do without hurry and when assemble parts back together, keep your hands and environment full clean, specially when working with bearings and cylinders. And remember apply oil to the cylinders and bearings when putting all back together.
 
Water pump impeller should be changed every 4 or 5 years on that motor.-----They will run and run ( with marginal cooling ) until they go " boom " like this one did
 
In 1993 they went to a bigger bore cylinder 2.375 " I believe.--And a different method of mounting the recoil starter.------So only a 93 to 2007 block will fit. ----Should not be hard to find I think.
 
That's right, Racer, all I have left is 92 and back. How about calling Tim's Outboard? Evinrudeman, can you post the picture of that old Merc you restored too? It's beautiful. Especially considering what resources are available there in Finland.
 
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