[cbcmarine]

So I have just taken the heads off this 1981 150 and it looks like it blew a ring and pounded the Piston and the head as well as scored the cylinder. So I have done lot's of snowmobile engines but never a outboard motor. I talked to a mechanic and he says throw it away, I can't see it, does anyone have leads for parts and a shop manual for this motor or am I wasting my time ??
Are the sleeves replaceable ??

Thanks

[Dhadley]

The sleeeves are repalceable but it's have to be damaged pretty badly not to be borable. There are .064" oversize pistons for that motor. As long as the block is borable and the crank & rods are OK, I'd say it's worth rebuilding.

[cbcmarine]

So are there aftermarket pistons ? and would you just do one cylinder ??
Anything I should know are there weak points to these motors ?
Wrist pins, rings ect
What would rebuild time be 10hs ??

Thanks for any help

[mikesea]

First consider the motor.its an 1981.Is it a super clean freshwater used engine with NO other problems.If so.You MIGHT want to rebuild.If you can do a snowmobile ,its easy enough.Having it bored may cost about $100.A sleeve needing to be replced ,200 250.It requires boring old sleeve out,installing a new costly sleeve and more machine work.Yes you can do one cyl.BUT,the engine needs to be totally stripped for machine work.At that point,a 81 engine likely has wear elsewhere,meaning 6 new pistons at at least 100 a PIECE,there are different after mkt. companies.then berings,gaskets oh and boring the other 5 holes,.you can look on the iboats website for remanufactured powerheads.But ,its still a few grand.You might do better to buy a good ,clean freshwater preferred engine for half the price of the rebuild.Its the material in this case that will cost you.In the end you still have a 1981 eng.if you keep it ,you know what you got .But how is the lower unit,trim and tilt?The 150 are great engines.

[iwombat]

There's both factory and aftermarket oversize pistons. Strip the block and get all the holes properly measured by a machine shop. If all the other holes are in spec it's worth rebuilding (pistons, rods, crank etc are all reusable). If not, you'll need to see what's worn, how much parts are going to cost you and weigh that against the price of a new powerhead.

[cbcmarine]

Thanks all
The engine seems very clean I bought it off a family last year that had it since new and has only seen two months use a year and has only seen fresh water.
I did order a manual so I will take the power head off and see from there, Any tricks I should know to remove the power head or should I wait for the manual??

Thanks all for your help I will keep you updated

[iwombat]

Originally Posted by cbcmarine

Thanks all
Any tricks I should know to remove the power head

No tricks, just good practices.

- Take lots of digital pictures before you start, and during the process. Can't have too many references to how wires were run, etc.

- Keep sets of parts (fasteners, odds and ends, etc) in labeled ziploc bags. i.e. Exhaust cover, intake manifold, carbs, etc.

- Place the bags and bigger assemblies in plastic boxes or sturdy cardboard boxes.

You'll save yourself a lot of grief by keeping everything separated.



Also, be sure to take a sharpie and mark the connecting rods, rod caps, and pistons 1, 2 . . .etc. They should all go back in the same holes.

[Reggie08]

Originally Posted by iwombat

No tricks, just good practices.

- Take lots of digital pictures before you start, and during the process. Can't have too many references to how wires were run, etc.

- Keep sets of parts (fasteners, odds and ends, etc) in labeled ziploc bags. i.e. Exhaust cover, intake manifold, carbs, etc.

- Place the bags and bigger assemblies in plastic boxes or sturdy cardboard boxes.

You'll save yourself a lot of grief by keeping everything separated.



Also, be sure to take a sharpie and mark the connecting rods, rod caps, and pistons 1, 2 . . .etc. They should all go back in the same holes.

Excellent advice right there! I just completed a rebuild and taking pictures and marking wires/plugs helped tremendously putting it back together. With the electrical part, if two plugs were plugged together, I marked both ends "P1" then the next set of plugs "P2", etc. Made it much easier remembering what plugged into what. Heck I still have all my blue masking tape on the wires just so I can check, re-check all my connections if there's a problem.

Get an OMC service manual, not a Seloc or Clymer's. The OMC manual is much better.

[Dhadley]

You really shouldn't have to unplug much of anything. Take the ignition & electrical off as a unit. I usually seperate the starter to save weight but that wire is very obvious.

[Benny1963]

im building one now 40 dollars a hole to bore 750 rebuild kit with bearings
have a good block and heads if ya need anything two holes bad on this block excellent crank front half matchs ,block if ya need any of it pm me
worst part for me is broken bolts [saltwater motor ] i bought a used 175 powerhead to put on in the mean time .it pumped 95 or so across the board
with tight bearings pulled inspection plates its a good used motor
i paid 450 but havent run it yet im in louisiana ,if ya need something pm me
got a good hook up on engine kits complete /not partial /if your block or crank is bad and you decide you want to do it let me know i know shipping is high so im not looking to make any money.

[cbcmarine]

Thanks All

Great advice and digital camera's have made a world of difference in assembly.
I will try to post some pic's for advise hope you all don't mind
Try to start this weekend
Happy boating