No oil pressure on 97 Monterey with 5.7

Efini Motorsport

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I'm picking up a new boat tomorrow. Found a 97 Monterey 210 cuddy with a 5.7gl volvo for a price I couldn't pass up. It's in good shape overall but the engine has no oil pressure ( the reason it is so cheap). The previous owner said he was out one day and everything was fine. He went to start the boat and it would run for a second then die. Tried a few times before getting towed in. When he brought it to his mechanic (a friend/ neighbor of his who is a marine mechanic) the mechanic did whatever diag and said he had zero oil pressure when a mechanical gauge was hooked up. I'm trying to figure out if there is an oil pressure sensor that could stop the engine a few seconds after it starts or if I'm going to have to start by replacing the oil pump. The engine has an aftermarket holley performance carb but I'm not sure if there is an electric or mechanical fuel pump. If I have to do the oil pump I'll just pull the engine and tear it down for a rebuild. If it's something external though it would be even better.
 

Efini Motorsport

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I'll be going through and doing my own diag on it but want to get ideas on other things to check or look out for.
 

tpenfield

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1997 there would certainly be an alarm for low/no oil pressure, but maybe a switch as well. You are probably best to pull the engine, since the oil pump is down in the oil pan and not accessible otherwise.
 

Scott Danforth

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I agree with everything Ted stated. also, pulling the engine is easy.
 

Lou C

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If it’s a 1997 it should have a Vortec engine which requires the electric fuel pump & the oil pressure switch to power the pump after the engine starts. I might before pulling the engine pull the distributor to see if the distributor & cam gears are torn up since the distributor shaft is what drives the oil pump on the small block Chevrolet….might even test it with the special tool in a drill to spin the oil pump with the manual gauge hooked up…
 
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Efini Motorsport

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Could it be anything else besides the oil pump? I just want some ideas of things to check before I pull it
 

Lou C

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The true test is the manual gauge, electric gauges can fail due to electrical issues.
Only other thing I can think of is if the oil was never changed & there’s a bunch of sludge in the pan & the oil pump pick up is clogged…
 

Efini Motorsport

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He seemed to take pretty good care of the boat. Pulled the dipstick and the oil was very clean. He's an older retired guy and used the boat every chance he could. This happened in early July and he he bought a newer boat within a few weeks
 

itsathepete

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May 23, 2018
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I have had a broken oil pump intermediate shaft that resulted in no oil pressure. Oil pickup tube can fall off. Pull the dizzy and check intermediate shaft. And make sure dizzy shaft is intact
 
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