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Message |
    
mercator30
New member
Username: mercator30
Post Number: 1
Registered: 01-2012
| | Posted on Saturday, January 28, 2012 - 12:35 am: | 
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Hi all....I am beginning to lose hope in my sailboat engine a MD2B. The engine and boat are a recent acquistion with low hours. It has been running excellent and today I ran into a oil pressure problem. CHecked the oil and although it is always hard to see on the stick I could tell that it was full. Started it up and ran it at the dock for about 15 minutes. Then when going back to shut it off I noticed the low pressure oil light was on. I immediatly checked the oil and discovered that it had several quarts of diesel mixed it (did this once before several months ago but had not repeated till now, another issue to be resolved). I changed out the oil, restarted the engine, still the low warning light. Replaced the oil sender with a oil pressure gauge with accompanying plastic hose from gauge to sender, started the engine, no pressure. Pulled the oil pump, primed with some 2o weight generator oil till full, replaced and started engine, no pressure. I did not let it run for more than 15 seconds with each of the test, for fear of the dreaded main bearing knock.
I am not sure how to proceed, I dont have new gaskets for the oil dip stick so I will try that but i cleaned up the surfaces and reseated so I think they are good. I havent rebuilt the oil pump yet so I can do that...but what if these remedies dont fix it, do I have dramatic bearing wear without a knock? is that possible?
Thanks in advance for any wisdom you can share
R |
johnoxley
Senior Member
Username: johnoxley
Post Number: 51
Registered: 04-2010
| | Posted on Saturday, January 28, 2012 - 04:30 am: |
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Hi - You need to check your oil gauge first. Do not know if you have mechanical (direct pressure) gauge or an electrical sender + gauge. Suggest you get a known good mechanical gauge and a tee (1/4" pipe?) and insert it into the system at the existing oil gauge connection at the block. Start your engine and see of this gauge reads low - if so, you have a problem with a blown oil line, defective bypass valve or oil pump or something else is wrong. Is the oil pump drive sheared off? |
mercator30
New member
Username: mercator30
Post Number: 2
Registered: 01-2012
| | Posted on Saturday, January 28, 2012 - 08:18 am: |
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John, my system has a mechanical direct pressure gauge. I also immediately questioned the sender unit or gauge and tried installing a new aftermarket mechanical gauge by removing the old sender unit, installing a adapter in its place with the new gauge, no oil pressure.When I pulled the oil pump and turned the camshaft drive on it, I could hear the pumping action and the oil I was squirting into the intake hole on the pump immediatly pumped thru the pump, seems like the pump is ok? I have not checked the bypass valve or for blown oil lines, will need to read up on how to do this. Just seems odd that this happened so suddenly and that the engine ran at first for an unknown amount of time with the low oil pressure light on and didnt start making noises.
r |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 102
Registered: 12-2009
| | Posted on Saturday, January 28, 2012 - 10:28 am: |
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Have you resolved the diesel in oil problem? That would be the immediate cause of low oil pressure.
When you say "low oil pressure" what, exactly is the reading (when there is no diesel in the oil)? When warm these engines, these engines usually run around 20psi.
Was the engine recently rebuilt? |
mercator30
New member
Username: mercator30
Post Number: 3
Registered: 01-2012
| | Posted on Saturday, January 28, 2012 - 10:37 am: |
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I have checked the engine after the quick test starts and no diesel was found in the oil. When I hooked up the mechanical oil gauge ( a add on unit as my stock setup is only a oil light that comes on with low pressure) oil never ran into the clear plastic tube that feeds into the aftermarket gauge, and no oil pressure was shown on the gauge. I acquired the boat and engine six months ago and the engine only had 500 logged hours per the log book and owner with regular oil changes logged also. The engine has never been apart.
I am thinking I should repull the oil pump and re prime it, make sure that it gets a good seal to the block when remounting it, and see if this gets the oil pressure back? It has never had a oil pressure issue before and when started for the two test starts, starts quickly without any new noises.
Puzzling to me and nerveracking. |
mercator30
Member
Username: mercator30
Post Number: 4
Registered: 01-2012
| | Posted on Saturday, January 28, 2012 - 10:41 am: |
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My immediate thoughts are that either the prime was lost in the pump due to the thinned oil and it is having a hard time getting prime back or there was significant wear on the main bearings when ran with the diesel in the oil that is now not allowing a build up of oil pressure, this is my biggest fear, but it seems like I would have a knocking noise if that had occurred? |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 103
Registered: 12-2009
| | Posted on Saturday, January 28, 2012 - 11:02 am: |
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Drain the oil and replace with 50wt. Remove the oil pump, disassemble, clean and re-assemble with new gaskets and shim. |
mercator30
Member
Username: mercator30
Post Number: 5
Registered: 01-2012
| | Posted on Saturday, January 28, 2012 - 11:10 am: |
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Sounds like a good idea Matt...off to the store for 50 wt..should be able to retest within a couple of hours... |
matt_morehouse
Senior Member
Username: matt_morehouse
Post Number: 104
Registered: 12-2009
| | Posted on Saturday, January 28, 2012 - 11:24 am: |
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I notice you are in Oregon. I have some parts that I have been trying to give away if you're interested... |
mercator30
Member
Username: mercator30
Post Number: 6
Registered: 01-2012
| | Posted on Saturday, January 28, 2012 - 12:06 pm: |
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Matt, you know a true diesel addict can never have enough spare parts. I am very interested in any parts you could "donate" to my ongoing "cause". Even though I live near Portland Oregon the boat is near Coos Bay, not exceedingly far from you in Eureka. We should chat offline about what you have in your "donation" pile. Just sent you a email to chat more on this. Wish you were nearer the boat, would offer to hire you on this gorgeous winter day in Bandon to help get this vintage metal humming again. |
