Free boat,shot engine

lucid484

Petty Officer 2nd Class
Joined
Oct 5, 2008
Messages
175
Ok well i got a free boat with a blown engine from a friend..the engine is a 1995 Johnson 150hp engine model 150ELEOM

the dealer that my buddy took it to had the heads off of the engine...so I could see the damage when he gave me the boat....all the pistons look fine except the top one on the starboard side...looks like the top of it melted and small pices of molten metal like sesame seed on the piston and head....well the dealer said that when they started taking it apart that the rods and everything were fine,and it just look like the rings failed from "sitting" for so long.

I found a site that has every single tiny part for that specific engine....and the good news is that every cylinder has a sleeve.soooo what my thoughts are is to remove the power head and bring it to a local machine shop..have them remove the sleeve and press a new one in. From what a found for parts Top of head is $256,Piston and rings are about $110 and a OEM sleeve in $28.

so if all goes well and thats all i need with labor etc. i'm hoping that it might cost less than a grand.

next week we me and a friend are going to remove the power head and lower assembly and bring them into the basement of my aprtment...Im actually going to tear the engine down so see for my self if that was the only damage.price wise a new/rebuilt power head runs between 3-4k and a new 150 engine is over 10k!!! so with the economy being as it is and i pay cash for every thing it would be 1-2 years before saving to buy a new powerhead.so if dont get anywhere from tearing it down at least i will gain some knowledge!

also i think the guy at the dealer said the guy may have put a 94 power head on it...and the electrical was all messed up (when my buddy first got the boat it didnt run right,cost a $1000 for the dealer to redo the electrical/ignition)


will post pictures tomoroow...and insight from you johnson guru's would be great
 

jonesg

Admiral
Joined
Feb 22, 2008
Messages
7,198
Re: Free boat,shot engine

I'm not one of the gurus here but own a J150 so I've read just about everything written,

I am fairly certain you can install new (larger) piston, rings and bore the cylinder .020 over, pistons run around $120, machine shop might be $200 , so its gonna be a lot less than $ 1K to do one hole.

be absolutely carefull to keep all the cylinder parts together in their sets, if you mix up the bearings from the crank/rods they will have to be replaced, its ez to make a $600 mistake and have to throw away good parts.
Get a factory masnual if you don't already have one from www.kencook.com

if you hang around here you won't be needing any mechanic.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Free boat,shot engine

Bombardier makes .030 over pistons which will match the originals in weight. Worth it to see if the block will cleanup with an overbore first.
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: Free boat,shot engine

Lucid, I think you have a good plan to repair that motor. However, I doubt the motor blew from "sitting too long". For your repair to last, you need to determine the cause for the failure and fix it. As a minimum, rebuild all six carbs, re-link and sync the ignition, and install a new waterpump impeller and thermostats. Run some premix until you are sure the OMS pump works. it is not likely the OMS caused the failure, but it is necessary to see that it works properly.

Also, look closely at the other pistons. Check for wear on the piston ring locator pins. Check the crank for water marks and chatter marks.
 

lucid484

Petty Officer 2nd Class
Joined
Oct 5, 2008
Messages
175
Re: Free boat,shot engine

Lucid, I think you have a good plan to repair that motor. However, I doubt the motor blew from "sitting too long". For your repair to last, you need to determine the cause for the failure and fix it. As a minimum, rebuild all six carbs, re-link and sync the ignition, and install a new waterpump impeller and thermostats. Run some premix until you are sure the OMS pump works. it is not likely the OMS caused the failure, but it is necessary to see that it works properly.

Also, look closely at the other pistons. Check for wear on the piston ring locator pins. Check the crank for water marks and chatter marks.

ok will do....i have to order the manual so i can figure out how to take the head off....i know the engine weighs a ton so maybe ill just bring the head home and leave to lower unit attached to the boat.

yeah the only info i know is that the dealer told my buddy the previous owner had the ignition all screwed up and possibly had a different year powerhead on the motor...and that from what they can tell it was just the rings that got screwed up and eaten by the piston.
 

lucid484

Petty Officer 2nd Class
Joined
Oct 5, 2008
Messages
175
Re: Free boat,shot engine

here are pics of the top of the head cover,bad piston an other good pistons (other ones are fun but alot of sludge build up).
 

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14ftgrumman

Chief Petty Officer
Joined
Jul 19, 2008
Messages
416
Re: Free boat,shot engine

What's going on with the piston in pic no.3? That doesn't look too good, either.
Ring or ring land curling up?
 

lucid484

Petty Officer 2nd Class
Joined
Oct 5, 2008
Messages
175
Re: Free boat,shot engine

hahah no thats just some gunk i scraped away with my finger...
 

lucid484

Petty Officer 2nd Class
Joined
Oct 5, 2008
Messages
175
Re: Free boat,shot engine

anyone else have any insight on weather replacing that bad piston would be feasible and i that motor is indeed sleeved?
 

Chinewalker

Fleet Admiral
Joined
Aug 19, 2001
Messages
8,902
Re: Free boat,shot engine

I would definitely rebore that cylinder to .030 oversize before I attempted to resleeve. Resleeving is much more than simply pressing in a new sleeve. Reboring is easier and will work just as well...
- Scott
 

lucid484

Petty Officer 2nd Class
Joined
Oct 5, 2008
Messages
175
Re: Free boat,shot engine

will i have to rebore all of the cylinders though?
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
28,074
Re: Free boat,shot engine

You may bore only the bad cylinders. Oversize pistons are made to weigh he same as std pistons, so you may mix and match 'em.

Do you think that the piston rings have rust on 'em? It looked that way from the photo. You need to find out why, and fix it.
 
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