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Old 05-11-2012, 08:33   #1
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Yanmar 3GM30F Rebuild Rookie - no oil pressure

Everyone

After rebuilding my Yanmar 3GM30f we bench tested it yesterday, ran it at 600 rpm and there does not seem to be any oil pressure at all. The oil pump was replaced during the rebuild. No oil is getting to the oil filter or the oil pressure sensor.

Any advice as to where we should start looking?

Thanks again

Gary
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Old 06-11-2012, 17:29   #2
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

These oil pumps are positive displacement pumps, therefore if they are engaged and turning the oil must be going somewhere. Start by ensuring that the drive is properly engaged and the gear wheels are in fact turning. With the oil pressure sensor removed you should be able to turn the engine over with the decompression levers lifted until oil is seen at the sensor and likewise for the filter. Once this is established you know the pump is working. Then look for an open plug in the oilways such as the crank shaft bearings, head gear etc, it has to be going somewhere.

Good luck

Acushla
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Old 06-11-2012, 19:34   #3
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

Maybe the sensor itself or the gauge.
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Old 09-11-2012, 13:18   #4
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

I have seen similar problems with new oil pumps in older gas engines. The solution at those times was priming. And of course, Frz's above post could be the problem especially if the wiring was removed during rebuild and not properly reinstalled. Good luck--
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Old 12-11-2012, 07:31   #5
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

OK, here's what we have done.

There is no electrical hooked up (engine is on the bench) so no gauges. With the compression levers flipped and the oil pressure sensor removed, we turn the engine with a large electric drill. No oil appears at the pressure sensor site, and no oil makes it to the filter. It seems that the oil pump is not primed. How do we prime it?

Thanks for you help

Gary
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Old 12-11-2012, 13:46   #6
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

To assist the priming of the pump you can fill the filter as much as is possible before fitting and inject oil into the sensor line until it is filled. Turn the engine by hand both backwards and forwards to get the oil into the gears. When turning backwards you should see the sensor line level go down and vice versa when turning forwards. Turning the engine backwards is the most beneficial as it puts oil through the pump and down the suction pipe to the sump. Once this is established you should be good to go.

Acushla
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Old 12-11-2012, 14:05   #7
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

An oil pump should never need priming as it should be submerged in oil.
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Old 15-11-2012, 01:27   #8
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

Sorry DeepFrz but most oil pumps are above the oil level and often need some help for the initial priming
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Old 19-11-2012, 08:13   #9
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

Acushla your suggestions did the trick, pump is primed and we have oil pressure.

Thanks a bunch!

Gary
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Old 19-11-2012, 21:23   #10
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

Next time pack the gears in the pump with white lithum grease
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Old 19-11-2012, 21:48   #11
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

Quote:
Originally Posted by NoTies View Post
Sorry DeepFrz but most oil pumps are above the oil level and often need some help for the initial priming
Oil pumps are above the oil level...? huh? you mean with a pickup tube a few inches in the oil right?
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Old 20-11-2012, 07:11   #12
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

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Oil pumps are above the oil level...? huh? you mean with a pickup tube a few inches in the oil right?

No take the pump apart and pack the gear cavity with lithum grade grease o (engine assembly lube),then reassemble it . It will always prime and save you a lot of work
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Old 23-11-2012, 18:05   #13
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Re: Yanmar 3GM30F Rebuild Rookie - no oil pressure

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Oil pumps are above the oil level...? huh? you mean with a pickup tube a few inches in the oil right?
That's correct. I've just replaced an oil pump on a 800kW engine that was about 500mm above the oil level.
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