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1987 Mariner tear down

J

John Heaton

New member
Problem: Need to rebore block and replace all pistons in my 1987 Mariner 150 hp 2 stroke due to failure of oil mixer (burned up two pistons).

I have separated the power head from the lower unit but I cannot break the block apart to remove the "jugs" for machining. Pistons move freely and the motor is not seized up.

I just need to know how to get the block broken down entirely. Do I need to remove the intake side or are there hidden bolts that I have not discovered?
 
Racerone - thanks for the quick feedback. I suspected that was what I had to do. So, next question...is it best to remove all electrical wiring harnesses or to work around them?
 
Really ???-----All electrical bits should be off this motor in order to do this job.----No manual ?----Working on your first motor ??
 
Motor has to be stripped,carbs and intake removed, and sleeves are cast in block. Can bore up to .040 and suggest cast not forged pistons. Also discard the idle stabilizer.
 
racerone said:
Really ???-----All electrical bits should be off this motor in order to do this job.----No manual ?----Working on your first motor ??
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Yeah. First motor for me. I have Seloc's manual, but it is of very limited value, and there are very few YouTube videos the demonstrate what I am trying to do. I live in a part of the country with no marine mechanics within an hour's drive.

I spent the morning stripping the electrical, etc. and taking lots of pictures. I got the intake manifold loose without taking off the carbs, but, of course, it won't come off the block. Seems to pivot and hang up on the left side.
 
Before burning up the pistons I had $1500 worth of rebuild in the carbs, so I am hesitant to take anything apart regarding them. I was hoping I could leave them attached to the manifold and remove as a unit.

Your advice is welcome.
 
Okay, thanks. Can carbs be removed without separating them from the manifold??? I have the manifold loose, but it won't separate from the block.
 
That, along with some other service on the prop, etc. Can you tell me if the carbs have to be removed from the intake manifold to get the manifold off?
 
faztbullet said:
Carbs can stay on but fuel pump need to be removed as bolt behind it.
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Hey, thank you for the response. After disconnecting all the intake bolts I suspected there must be a bolt behind the fuel pump. Thanks for confirming. BTW, I am 56 yrs old and have never torn down a marine engine. Thanks for your patience and willingness to respond.
 
racerone said:
Looks like the plastic gear that drives oil pump is stripped.----What do the bearings look like ???
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The ball bearings at the bottom of the crankshaft look fine. I don't think any "big" particles worked that far down. Of course, fine metalic particles could have moved even into the lower unit, but I doubt it. I ran a magnet over the "mud" and, as expected, picked up a bunch of crap.

Next move is to get the pistons off and get the short block to a machinist. That will tell the story. By the photo, I would be expecting to buy a new short block.

What do you think?
 
There is no way that fine metal particles can find their way into the lower unit.----Find a manual .---Read it twice before going further.
 
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