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Calaban-Alleria · 10-08-2023, 18:45

Recently we had a “zero oil pressure on startup event” when starting the engine in preparation to enter a marina. Long story short - cant say enough good things about the Canadian coast guard. Along with great help from great friends we sailed back to home port without a working engine.

Now to fix the problem:

I have diagnosed the issue to the gear driven oil pump (two independent sensor reporting zero, no suction, oil pickup intact etc). At this point I am working on the disassembly to get at the oil pump. It looks like this should be relatively straightforward once the front gear case is removed.

I have removed the alternator, throttle and stop control lines, water pump">raw water pump and crank pulley and disconnected the fuel supply, and fuel delivery lines leaving the front assembly unencumbered:

At this point I removed all the retaining bolts and expected to slide the gear housing forward and off of the engine exposing the oil pump.

The housing will slid forward not quite a half inch and stops. No amount of wiggling or cursing will move it any further.
Is there something else I am missing?
Do I have to remove the fuel injection pump from the housing?
Does anyone have any experience with this?

Thank you.

wsmurdoch · 10-08-2023, 19:38

From the Seloc manual...

(If that helps, send me a PM with your internet address, and I'll send you the file.)

Calaban-Alleria · 11-08-2023, 10:34

Thank you wsmurdoch that looks like good information.
There must be some kind of law of nature that any job you haven't done before will be more complex than you imagine!

**skipperpete** · 11-08-2023, 14:27

YES to removing the injector pump and you need to clean up or polish the manual starter stub so it will slide easily as you withdraw the timing cover.
Usually its wise to first examine the relief valve and the oil filter before diving into the oil pump removal and you also might need to include the suction pipe in the oil pan as part of your hunt for the loss of oil pressure.

milagroman · 11-08-2023, 15:47

You may also want to join this Facebook group of Yanmar engines repairs and ask your question. Amazing wealth of knowledge and good people. https://www.facebook.com/groups/4657...ibextid=NSMWBT

Calaban-Alleria · 17-08-2023, 17:58

Turns out that yes the injection pump should be removed before the gear case is slid off..

The injection pump has cam followers. In this case three of them (3 cylinder engine).

As I tried to slide the gear case forward off the engine the cam followers would hang up on the next cam lobe. Kinda obvious now when I think about it.

By manually turning the engine over a bit at a time and wiggling the case I got it to come free as turning it moved each cam lobe out of the way as the engine was rotated.
I now have access to the oil pump in all its glory!

Calaban-Alleria · 20-12-2023, 15:07

Just to update anyone who read this thread - in due time the replacement oil pump and gaskets etc arrived and I successfully got engine assembled and running well. It does have about 10 pounds more oil pressure than the gauge showed in the past.

Thanks everyone who replied.

**Wotname** · 20-12-2023, 15:18

Thanks for the update, it is always good to hear the end story

.

wsmurdoch · 20-12-2023, 19:17

Is that the 0 psig from a "zero oil pressure event" plus 10 psig for a total of 10 psig or something higher?

**skipperpete** · 20-12-2023, 19:52

Quote:

Originally Posted by Calaban-Alleria

Just to update anyone who read this thread - in due time the replacement oil pump and gaskets etc arrived and I successfully got engine assembled and running well. It does have about 10 pounds more oil pressure than the gauge showed in the past.

Thanks everyone who replied.

Thanks for the update, well done ..
Can you give us any clues about what was wrong with the oil pump that caused zero oil pressure ?