Yanmar 1GM10 - Help Please

[raven]

I am posting this on behalf of Dogwatch who is incommunicado at the moment.

He has just re-fitted one of his his Yanmar 1GM10 engines after a full rebuild.

All connected up and fired up the engine runs but the oil pressure warning light stays and on and the buzzer sounds. The engine appears to be running freely and there is plenty of oil.

He wonders if he needs to run the engine for a time to get pressure up but is loathe to let it run with the warnings sounding.

Does anyone have any advice I can pass back to him?

Thanks

 

[yoda]

Is oil getting up to the rocker gear? If it is then the pump is unlikely to be at fault. Check the sensor and continuity of the wiring to and from it.

Yoda

 

[VicS]

[ QUOTE ]
Check the sensor and continuity of the wiring to and from it.


[/ QUOTE ] Or for a short to earth!

 

[lw395]

1) check the wiring, does the light go out if you disconnect the sensor?
2) Check the sensor, either substitute a new one or connect a gauge in its place. Or just take the sensor out, oil should squirt out if you turn the motor over.
The oilpressure should rise enough to switch off the light by spinning over decompressed. It may take a few seconds to fill the filter.
If the filter is empty after 30secs of turning over, there is a problem!
Do not let the engine start in the hope that the problem will go away!
It may be the pressure relief/regulation valve which limits the pressure to 50psi or so, can get stuck open.
Good luck!

 

[raven]

Thanks guys,

I have passed on your thoughts to Dogwatch - via a dodgy telephone link - he is a cussing and a hollering down in the bilges of his boat - will try and get some feedback when he reports progress.

 

[misterg]

Gawd, I was down there today, too. Started raining, so I didn't go down to the harbour....

Echo what "LW395" said:

Simple diagnostics - pull the wire off the sender, turn on key, is the oil light lit?

If "Yes" then it's a wiring fault (short to earth between instrument panel & engine). If "No" then it is a sender or oil pressure fault. Suggest he then swaps the sender with the one on his other engine and verifies whether it works correctly or not. If it does, then he's got a real oil pressure problem.

I don't know anything specific to the 1GM10, but general points: Did he fill & fit the oil filter before filling the sump? If so, it's just possible that he's air-locked the oil pump - Maybe take the filter off & re-fit it to allow it to 'burp'. Has he had the oil pump off? if so, was there a key in the drive shaft? is it there now?. If he hasn't filled the filter, then perhaps it just needs time to fill? If he hasn't touched the filter, but drained the sump and turned the engine over (by hand) then he may also have air-locked the oil pump.

Whatever; If he has verified that it is indeed an oil pressure fault, then IMHO, he shouldn't start the engine - when you think the problem has been solved, spin it over with the decompressor on and verify that there's oil pressure before starting. If the engine has been oiled on re-assembly it will run for a few minutes, but don't be fooled!

Andy

 

[raven]

Thanks Misterg,

Have relayed your message to Dogwatch and it has set him thinking.....

It's sounding more like an electrical problem than a mechanical one.

 

[misterg]

[ QUOTE ]
It's sounding more like an electrical problem than a mechanical one.

[/ QUOTE ]

Let's hope so. He must be pretty pee'd off !

Andy

 

[wotayottie]

Been there and got the T shirt on a problem which sounds similar to this one.

I bought a new engine that had been in stock for a while and installed it instead of an o/b in my then Hunter. First second and third start ups gave no oil pressure and the warning buzzer sounding, so I contacted Yanmar. They explained that the oil pump itself would have lost its prime (as would happen with a complete strip down) and the cure was to have the b*lls to rev the engine briefly to half revs until the buzzer stopped. To say the least I was nervous and I got them to put the instruction in writing. They re-assured me that the oil in the bearings after assembly would be enough for a quick run up to these revs. It was - the light went out and stayed out - the engine ran for years with no problem.

This is the reason why you arent encouraged to drain the engine oil in the normal fashion from the bottom of the sump.

Now you might well have some other problem with your engine that is causing the lack of oil pressure so if you try the above you do so at your own risk. I can only tell you what worked for me with my engine and yous might be a different problem altogether. Probably the best thing to do is first to talk to the engineers at Barrus or alternatively to the engineer that has re-built the engine. After all, if there is anything else causing the problem, its his responsibility not Yanmars.

P.S. I seem to remember (it was 10 years back) that I also used an oil can to inject engine oil into the openings behind the oil filter before attaching the filter and running the engine

 

[cliffordpope]

My new one came in a crate with no oil. There were no instructions about reving it up - the oil presure gauge registered a second or two after first starting.

I don't see how the method of draining the oil can make any difference. Leaving say 1/8 inch of oil in the bottom of the sump isn't going to prime the pump, if that's what it needs.

 

[wotayottie]

Well take it from me that it does!

My guess is that the oil pick up is well down in the sump itself and draining the oil completely lets air into the pick up which the pump cant expel at engine idle speed. Either way, I did what the Yanmar engineer told me to do and it worked exactly as he said it would on an engine that never gave the same problem again and ran like a swiss watch (or should I say a Seiko). That also was a new engine in a crate - in fact I've still got the crate if not the engine

 

[ShipsWoofy]

Thank you Raven for posting this and thank you all for your responses to my drama.

When I first fitted the engine and the warning started, I decided it would be most probably electrical, I trust the engineer who has just honed the cylinder and fitted new rings for me. The head has recently been rebuilt and polished at an engineers so I am sure that too is ok.

The first thing I did was check continuity from the panel to the LO sender, this was showing a dead short, so I swapped the LO sender from the other engine, this did not stop the warning, the other engine with the now swapped sender did not alarm.

Following advice from here I broke the circuit by disconnecting the wire to the sender, this blanked the buzzer and the indicator went out, this means the circuit is working.

So it is oil. I contacted the mechanic and told him of my fun, he was quite shocked, he has a yanmar panel at the workshop and assured me it did not show any problems when he ran the engine up after rebuild, he is not the sort who would send an engine out like this. He did admit to not measuring the actual oil pressure, but as this engine has not had oil problems in the past it did seem a moot point, which I agreed with.

After speaking to him, and Alan who called me to update messages given in this thread; I whipped the oil filter off, this was empty, which I assume indicates an air lock in either the filter assy or the pump. With the filter off, I turned the engine on the handle and no oil pumped, though I can hear the oil pump sucking (or blowing). I tried to fill oil into the filter outlet to create a vacuum but this had no effect. I then filled the filter to the brim with oil and replaced it.

I started the engine and gave it a few tweaks for up to 30 seconds and bottled it and shut it down.

Unfortunately, the mech is out of the country for a week so I am left in the air a little. I will telephone barus today for advice, it is difficult to keep it running knowing the pump is dry.

I did consider dropping the oil and refilling on the off-chance it might clear any air locks, but yesterday I was in a serious state with my crappy crippled bones so it will have to wait now. Another part says it is not my problem and I just wait until the mech can get on board and see for himself.

Another strange thing, maybe, when I removed the oil filler cap, the sound of the pump sucking stopped, I don't know if this means anything or not, the workshop manual really breezes through the lubrication system with very scant information. It does not mention air-locks or any problems following rebuild at all.

Once again, thank you all for advice, it did help. I am sure this is going to be a simple fix, I have not the energy for anything else right now, even my fingers hurt typing this /forums/images/graemlins/frown.gif

J

 

[wotayottie]

The original post from Raven didnt mention that the engine had already been run up post re-build and had given good oil pressure - so it doesnt sound like my experience with a new and completely drained engine. Suggest you leave the whole issue to the mechanic who repaired the engine - its his responsibility if it doesnt now work. More to the point, there is only a short limited time you can run without oil pressure and relying on the oil put in the bearings during assembly before you do serious damage.

 

[misterg]

Oh dear! - you have my sympathy /forums/images/graemlins/frown.gif

[ QUOTE ]
...the mechanic [...] assured me it did not show any problems when he ran the engine up after rebuild....

[/ QUOTE ]
[ QUOTE ]
....I whipped the oil filter off, this was empty

[/ QUOTE ]

What has happened between the engine being run up by the mechanic and it being re-fitted to your boat? Unless it's had a new filter fitted, the two statements above are contradictory.

You shouldn't be able to hear the oil pump (general statement, not 1GM specific) - if there's gurgling and slurping going on, it means it's running in air.

Silly, silly question: Is there any oil in the sump? (Could it have spilled out while the engine was in transit?)

With the filter off, the oil should be able to find its own level, and clear any air-locks, particularly if the pump is turning, too. How long did you turn the engine over for when you had the filter off (with the handle)?

I don't know about this engine, but it's sometimes possible for the oil pick-up tube to fall out of the pump (and rattle around the sump).

I wouldn't run it again until you can see oil pumping out of where the filter should be (turn by hand, or spin on the starter with decompressor on). The more I think about it, though, if there isn't an innocent explanation for that filter being dry (i.e. you have changed it), then I would give it back to the mechanic without doing anything more.

Recognise that you're on borrowed time regarding lubrication - you really want to know it's been sorted before starting it again - spin it over as above to build up oil pressure and get some fresh oil around the system before starting it.

Engines make a horrible noise when they die, and you really don't want to hear it (Fiat tractor engine, sheared oil-pump drive ca. 1982 - this after re-grinding crankshaft, etc.)

Andy

 

[cliffordpope]

The advice against draining the oil via what looks like a drain plug at the front of the engine is that the plug also holds in place a vital clip or something to do with the oil intake pipe.
Could this have become misplaced or not assembled correctly during the rebuild?

(There is a proper drain plug, much less accessible, underneath the starter)