Top bearing is not getting enough oil, crossflow 90hp

Joined
Jun 10, 2011
Messages
21
Guys,

Since i had 2 cilinders scored, i opened the engine investigating and checking everything,
i noticed the lack of oil at the upper bearing. It has nothing to do with the 2 cilinders but i know this is not supposed to be like this. Bearings need oil.
All intake canals are open, but it just seems the oil is not traveling up:(
Is there something i can do to help the oil migrating to the top?
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DSC_4752klein.jpg

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Joined
Jun 10, 2011
Messages
21
Re: Top bearing is not getting enough oil, crossflow 90hp

Hi there commanders,
i really need some help here, to get this solved. I tried the search button with no luck.
How does this top bearing get his oil feed?
 

clanton

Rear Admiral
Joined
Jul 9, 2001
Messages
4,876
Re: Top bearing is not getting enough oil, crossflow 90hp

check and clean all recirclation hoses and nipples, the nipples in the block/intake are one way check valves. routing of hoses depends on year of engine. Early engines should be upgraded to 1990s hose routing.
 

Haffiman

Commander
Joined
Dec 17, 2009
Messages
2,454
Re: Top bearing is not getting enough oil, crossflow 90hp

In addition to the check-valves, check that nipples in the by-pass covers are open as well as all channels in the intake manifold. Do not use any sealer on intake gaskets!!

PS: It may has to do with scored cylinders as if no excess fuel from bypass covers, no lubrication to upper bearing!!
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: Top bearing is not getting enough oil, crossflow 90hp

Do an autopsy on the upper carb. Make sure there is no debris in the carb jets, esp the two mains in the upper bowl. You'll need to pull the jets out for a visual inspection. Also remove and inspect the needle and seat.
 

1946Zephyr

Vice Admiral
Joined
Oct 21, 2008
Messages
5,556
Re: Top bearing is not getting enough oil, crossflow 90hp

Is there an oil line on the side of the block? If there is, check and make sure it's not broke or clogged up. A lot of motors will have a return line that feeds the top bearing, from the bottom.
 

Joe Reeves

Supreme Mariner
Joined
Feb 24, 2002
Messages
13,262
Re: Top bearing is not getting enough oil, crossflow 90hp

See the oil feed hole in the top main bearing housing... first picture, facing straight up, very visible. Now, flip the forward crankcase housing over and follow the oil feed.
 
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