Changed oil today, now have zero oil pressure

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TexasA&M

New Member
Sep 14, 2009
213
Austin, Texas
Boat Info
2005 185 Sport
Engines
4.3MPI
Changed the oil in the boat today before I was going to put her up for the winter. Ran her for 10 minutes or so to get the oil warm, then did a standard oil change - drained oil, changed filter, then filled back up with oil. Cranked her back up to to fill up the filter before I did a final check and top off, and the oil pressure never would build up. I checked the filter, and it was bone dry. Put it back on and tried again, same result; zero pressure and dry filter. Didn't want to push my luck and run the engine dry too much longer, so I gave up for the day and was hoping that you guys could help me out. Any ideas as to what might be going on?

FYI, I have a 2005 185 Sport with 4.3MPI. It has a remote oil filter (which is mounted upside down), so I can't fill the filter up with oil before installing it. I am using the same Mercruiser filter than I had on there before and Merc oil. Temp today was about 55* (shouldn't matter, but fyi).

Any thoughts?
 
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That's weird. Try pulling the distributor and spinning the oil pump with a drill. Remember to mark the dist rotor's position AND the distributor housing's position.

When priming, it should be really loose at first but after several seconds the drill will labor as pressure builds. You'll also see oil starting to flow. If you don't have a prime tool, you can find them for about $20.
 
A dumm question, any change in the oil level, is it full? I would be surprized to see 2005 oil pump fail. So, hopefully there's something else going on.
 
No distributor for me.... it's all electronic. I thought about doing that, but not sure how without a standard dist on the back of the motor. No idea why it would work fine before changing the oil, and then not work afterward. Just doesn't make sense why it wouldn't be pumping ANY oil up to the filter.
 
A dumm question, any change in the oil level, is it full? I would be surprized to see 2005 oil pump fail. So, hopefully there's something else going on.

Thought about that, but it has 4.5 qts in it right now. It should technically run with much less than that. I don't think it's the pump either, mainly because it was working fine 10 minutes beforehand. I don't think the pickup is clogged either only because it would at least pump SOMETHING up to the filter. As it is now though, it is bone dry.

I'm hoping it's something simple too, but I don't know what I should do/try at this point.
 
This is really silly, but...you sure you filled it back up?!! I hate to even ask. But oil pumps are pretty basic devices directly driven by the camshaft in most cases. I've never heard of one just failing out-right, unless something really bad happened and then the engine probably wouldn't run.
I'd say your gauge went south on you, but you mention the filter was bone dry.

Keep us updated on this one, I'd be interested to hear what it turns out to be.
 
I doubt you would cause any harm by overfilling it in an attemt to prime the pump. I would add 3 or 4 more quarts crank the engine with the filter off. if oil comes up suck out the excess oil , clean the bilge and spin on the filter. if that doesn't work you might be in for a winter project. keep us informed
 
This is really silly, but...you sure you filled it back up?!! I hate to even ask. But oil pumps are pretty basic devices directly driven by the camshaft in most cases.

I checked several times because I was worried about the same thing... definitely have oil in the pan. It's to the 'full' line on the dipstick. I agree.... no reason that the pump should be broken. Engine runs fine, but I don't let it run for long. As far as I know, all of the pumps are driven by the cam in SBC motors. Nothing going on (except for the gauge reading zero) to indicate that there is any issue. The filter was definitely full of oil before I changed it (I spilled it all over the place). Tomorrow, I'm going to put the old filter back on and see what happens, just in case there is some weird issue with the new filter.
 
I only bought 5 qts, but will be getting more if necessary. Won't cause any issue overfilling it as long as you don't run it for long like that. Will try turning it over tomorrow with the filter off to see what happens.
 
Stupid question maybe but did you check to see if you bumped the oil sender wire off the sending unit? That would account for no reading on the gauge...

But as far as no oil in the filter, that makes no sense... I never heard of a defective filter... As everyone has said, the oil pump is run off the cam...
 
Never heard of a defective filter either, but it's the only thing I changed today. Crossing my fingers that that is what it is.... can't afford to have any major work done this year; can't live without my boat either!!
 
I've seen filters with no threads and some without gaskets. Make sure the old gasket isn't still stuck to the remote mount.
 
First of all STOP. As FC3 says pull the dis and buy a primer tool thats the dumbest thing I ever heard of!!! Waste of time and money

How about getting a good old manual oil presure gauge hooked up to the engine. That will tell you whats going on.

In all my days I have seen 1 bad oil filter. Buy or borrow the gauge Cheap answer!!
 
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He doesn't need a gauge. If there is no oil in the filter, he has no oil pressure.
 
OK but the gauge will confirm that. Electric gauges are not worth a sh*T does it start? if it does is it rapping? Doing unnecessary or money grabbing work is not the answer, its dumb. Also if it did run how long?
 
This is really silly, but...you sure you filled it back up?!! I hate to even ask. But oil pumps are pretty basic devices directly driven by the camshaft in most cases. I've never heard of one just failing out-right, unless something really bad happened and then the engine probably wouldn't run.
I'd say your gauge went south on you, but you mention the filter was bone dry.

Keep us updated on this one, I'd be interested to hear what it turns out to be.

I always fill the filter with oil before I put it on.
 
If you have no oil in the filter. As noted it is a defective filter or a blockage. One person I knew had a similar problem. He found what side of the filter was blocked by punching a hole in it. No oil came out so blockage was found at oil pick up in oil pan. I would try new filter first.
 
You said the filter is remote and mounted upside down. Lets go back to the beginning as this is where the problem started. Has something fallen into the filter base and clogged the hose? Take the line off the filter base and engine and blow them out. Bet something has fallen into them. I have seen plastic plugs and even popcorn packing in the filter that has clogged the filter base.

Most like likely the pump is good as you had good PSI before changing the oil. Do not restart the engine!! Follow Franks advice on priming the engine unless you find the hoses/filter base clogged.

Once you are sure you have removed the obstruction then fire the engine.
 
As FC3 says pull the dis and buy a primer tool thats the dumbest thing I ever heard of!!!

Not sure what this is referring to. Buying a secondary gauge sounds like a waste of money to me. I have no oil going to the filter, thus I have no oil pressure, whether the gauge is working or not. I'll deal with the gauge once I fix the bigger issue.

Again, I don't have a standard distributor, so I can't pull it to manually prime the engine. Spark is controlled electronically. Need to see if there is some other way to manually prime the engine though.

So far, I've only run the motor 30 seconds or so, just like you normally would after changing the oil. I'm going to start with trying the old filter today and see what happens. I did pour some oil down both tubes of the filter base yesterday.... oil went in without an issue. I can't remember though, which part of the filter does the oil enter, and which part does it leave? Does it enter or exit through the center of the filter?
 
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