Rebuilt 1988 MerCruiser 454 Oil pressure running high

mavrick86225

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Aug 6, 2012
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I have a 1988 Sea Ray with a 454 MerCruiser with 690 hours. I just had the engine and outdrive rebuilt from the ground up. My question is what should the oil pressure running at? I have seen post that say 60-70 when cold and then it drops back to 20-30. Mine is running at 60-70 and on long runs seems to being increasing to 80 and that is a high as the guage goes. The temp runs up about closer to 200 on long runs too.

Should I be worried or it is because it has been rebuilt and its not broke in?

Any advice is good. Thanks.
 

Don S

Honorary Moderator Emeritus
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Aug 31, 2004
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62,321
Re: Rebuilt 1988 MerCruiser 454 Oil pressure running high

Use a mechanical oil pressure gauge mounted on the engine to determine if you have an actual oil pressure problem, or a gauge problem. Also use one of those IR temp guns to see if the engine is actually running hot as well.
 

mavrick86225

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Joined
Aug 6, 2012
Messages
2
Re: Rebuilt 1988 MerCruiser 454 Oil pressure running high

Use a mechanical oil pressure gauge mounted on the engine to determine if you have an actual oil pressure problem, or a gauge problem. Also use one of those IR temp guns to see if the engine is actually running hot as well.

I am searching the site for directions to set up a mechanical oil pressure gauge. Any links would be helpful. Thanks.
 

Georgesalmon

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Apr 14, 2012
Messages
1,793
Re: Rebuilt 1988 MerCruiser 454 Oil pressure running high

Just get a mech oil gauge kit at your local auto parts store. Probably will come with everything you need. Then take out your current oil press sender and install the mech one in the same hole and use it like a test instrument. Unless you want to install it permanantly then get the brass fittings to put in a tee and run both. Most are 1/4 or 3/8 pipe thread (NPT). Size does not matter as you are measuring pressure and there is no flow of oil.
 
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