Upper Main Bearing

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dave 416

Seaman
Joined
Apr 15, 2007
Messages
58
I have a 1995 3cyl 50hp johnson that I am rebuilding .Top and middle cyl are toasted but I have had all three honed and bored .The question I have is that while placing the crank into the crankcase half the middle bearings all go into their locating pins but the top doesnt is it supose to
 
M

mikesea

Lieutenant Commander
Joined
Oct 1, 2006
Messages
1,830
Re: Upper Main Bearing

Are you saying it has a pin but the bearing wont sit into it.I had a couple engines over the yrs where the pin for some reason actuall got pressed into the hole as though when put together i didnt fit properly and got torqued down pushing the pin further into hole,I think this is what your saying,I was able to get a needlenosed vise grip and pulled the pin out ,i put a dab of JB weld into the holeso it held the pin from falling back inside
 
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dave 416

Seaman
Joined
Apr 15, 2007
Messages
58
Re: Upper Main Bearing

The problem is it wont go back far enough to go into the pin I think they built this motor with the wrong bearing
 
trendsetter240

trendsetter240

Lieutenant
Joined
Jun 22, 2009
Messages
1,458
Re: Upper Main Bearing

As you know I am rebuilding the same block and my upper main bearing locating pin was damaged. I haven't tried to re-assemble yet as my block is still in the machine shop.

Yes, the pin is supposed to go into the middle hole on the split sleeve. Are you lined up with the middle hole? How does the pin look? Does it appear damaged or flanged out at the top?
 
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dave 416

Seaman
Joined
Apr 15, 2007
Messages
58
Re: Upper Main Bearing

The two middle bearings are all lined up and on there pins the top pin is undamaged but the bearing is too long the bottom of it hits the counter balences on the shaft and the holes line up where that grove for the o ring is check yours when you get it back
 
trendsetter240

trendsetter240

Lieutenant
Joined
Jun 22, 2009
Messages
1,458
Re: Upper Main Bearing

:confused:
dave 416 said:
The two middle bearings are all lined up and on there pins the top pin is undamaged but the bearing is too long the bottom of it hits the counter balences on the shaft and the holes line up where that grove for the o ring is check yours when you get it back
Click to expand...

Ok, I just tried lining up my old crank and bearings in my block and it worked fine.

I think you have the upper main bearing on backwards. The seal must face up towards the flywheel.

the holes line up where that grove for the o ring is
Click to expand...

When I put mine on backwards, the holes line up where that grove for the o ring is.
 
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