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Old 16-09-2012, 06:18   #31
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

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Thanks, yes I know about the cooper washers.
Gee I hope the pump rebuild works for you but then again I hope I'm not up for one too.
I think the oil level relates to loading up the engine not causing oil to bypass the rings.
Spoke to a Yanmar mechanic at the Boat Show in Newport RI about these symptoms. He was VERY FAMILIAR with the problem. He said there had been a RASH of these problems on the 3GM engine that they had finally resolved.

He said to check the oil level. If it was at the full mark or slightly over then the most likely thing happening was that the lift pump was sucking engine oil into the fuel line after the oil had warmed up. It meant that the lift pump was perforated and needed replacement. The lift pump is a sealed unit and can't be repaired, so a new pump is needed. Then, of course, the oil and filter must be changed.

The quickest way to identify the problem is to pull out about a quart of oil and see if the symptoms persist.....

This explains a lot. It also points out how seemingly impossible it would be to troubleshoot this problem without expert knowledge. In the meantime, I've put out $800 to rebuild the injector pump and spent months going through the engine components and missing out on the sailing season.
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Old 16-09-2012, 10:02   #32
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So did you pull out some oil? Did the problem persist?

Don't assume before you test. We all want to know!
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Old 16-09-2012, 11:39   #33
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

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So did you pull out some oil? Did the problem persist?

Don't assume before you test. We all want to know!

I pick up the injector pump tomorrow and then put the engine back together over the next day or so. I'll keep you posted...
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Old 16-09-2012, 17:23   #34
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Thanks for sharing the info, I checked my oil and found it a bit high.
I tried to suck some out but part of my vacuum unit has disappeared so I've just ordered a better one (I hope).
Will post my results when I remove the oil.
I will look into buying a new lift pump too.
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Old 17-09-2012, 13:00   #35
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

I promised to give an update on my 3GM30 problems that matched the problems Terrylad was having, here goes in brief -

Early Signs
one year of white smoke only at high revs and occassional no turn on starting.

The Crunch
In August after a couple of hours at low revs - white smoke and clatter at above 1800 revs, limping into port the situation got progressively worse and problem occurred at all revs.

Since then -

Injectors removed and No3 found to be "stuffed"
Injectors refitted and problem still there.
Removed excess 0.25l oil from sump (checked this on a whim, was it over-filled?)
Injector pump removed and tested - no problems.
Engine still has same symptoms
Engine now worse and cutting out on trip to engineers boat yard (scary)
Engine run on seperate fuel system and same symptoms
Head removed and signs of washing on no 3 (fuel not being ignited at all)
Engine removed and dismantled - seized piston ring on no 3 and sump oil back up to over 6 litres.

Diagnosis -

White smoke was unburnt fuel and hard starting was hydraulic lock from liquid fuel in cylinder

Fuel eventually got into sump via seized piston ring and raised level above high - good reason to check your sump level!

Ultimately engine failure.

Cure

Injectors refurbished
New piston rings
New botton ends (dilluted lubrication risk).

Prevention

Establish if white smoke or steam in exhaust (a jamjar closed with the vapour / smoke inside and cooled in water might do this)

If smoke - get injectors checked before it gets serious.

Finally, avoid long periods at low revs - give the engine a good blow at around 2800 revs frequently!

Note of Caution

It's not over yet, engine to be tested and refitted this week!

Hope this helps.

Glyn
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Old 17-09-2012, 14:15   #36
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

You've really been through the mill with this. I didn't see any check on the fuel pump. I just checked mine and pulled it apart today. There was a perforation in the diaphragm - tiny, and also the braided fuel line to the filter was badly worn.

The IP is in place and I'm waiting on parts - new fuel pump, gaskets, etc., and then I'll start the business of putting it all together again, probably later this week.
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Old 17-09-2012, 15:31   #37
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Wow these problems sound similar to my engine. I hope I don't have the same thing! It would be an expensive fix.
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Old 17-09-2012, 15:38   #38
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Thanks for sharing your experience guys.
I've ordered a new pump from the UK, Aussie Yanmar parts are extortionate prices try $200 for a pump.

Extended idle and low revs or load are something I have always been told to avoid with diesels.

Was the seized ring believed to have been caused by fuel washing the oil away or did it glaze up because of the extended low load operation?

I hope it comes good for you, It seems like you have may have had two separate issues or one that has lead to another.

I would definitely have a look at your pump diaphragm though.

Were the bottom end bearings worn or damaged?
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Old 17-09-2012, 18:56   #39
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Actually thinking about it the pump diaphragm fits the symptoms.
I was originally told to check for a clogged fuel filter, which I found but it didn't fix the problem. But a drop off in fuel pressure from the lift pump under load would also cause fuel starvation. The high oil level is just a result of fuel leaking into the sump.
If you Google the symptoms there are a lot of people reporting this issue with their Yanmars on other forums.
It would be nice to find a report where someone has actually fixed the problem though.
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Old 18-09-2012, 00:50   #40
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Checking the fuel pump diaphragm is a good suggestion, thanks, I'll do it.

However I have routinely changed fuel filters in the past and they have always been clean.

Meant to say earlier that my engine hours are only 700.

Glyn
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Old 18-09-2012, 01:29   #41
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

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Checking the fuel pump diaphragm is a good suggestion, thanks, I'll do it.

However I have routinely changed fuel filters in the past and they have always been clean.

Meant to say earlier that my engine hours are only 700.

Glyn
Gee that's low hours to be having issues.
Clean filter rules out contamination damaging the diaphragm.
What year model is is your engine?
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Old 21-09-2012, 06:20   #42
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Progress: New lift pump and flexible braided fuel hose installed. The engine filter had waxy deposits - cleaned out. Reassembled heat exchanger, fresh water pump, thermostat, exhaust elbow etc. Reconnected throttle cable and bled the system.

Finally started up, but the engine couldn't maintain idle, it would rev down to below 500rpm and stall well before the idle stop. It felt like the IP rack was misaligned. Either that or the timing is far out - I used the same shims, but one was buckled from the service guys. I'll call the shop and see if there's rack alignment issue. Timing the engine is another issue, I have yet to figure out how to turn the engine, find the timing mark and coincide it with #1 fuel squirt - might have to recruit help.

At least its running and everythings tight so far. To be continued...
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Old 22-09-2012, 14:53   #43
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Done. The saga is over. The engine runs like clockwork. The stalling problem was due to me installing the idle screw plate the wrong way around.

Lessons learned - the fuel pump was the problem, it has just a tiny wear spot on the flexible part of the diaphragm, coupled with a suspect flexible braided pipe from the fuel pump to the filter. I should have saved the IP rebuild until the last resort - I retrieved the old parts and they're perfect, no wear or muck on them at all. Oh, well.

So, spread the word on these symptoms - check the fuel pump asap. This episode has taken me all summer to get to the end. Fortunately I don't have deep seated problems on the engine, such as broken rings, lower end or even head gasket problems, but I guess its guaranteed to happen at some point in the future.....
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Old 22-09-2012, 15:18   #44
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Re: Replacement Of Fuel Injectors For Yanmar 3GM30

Hi Terry,

Glad to hear that you are up and running again.
Sorry that you had to take such a tumultuous path to get a solution.
Thank you for sharing your experience and hard gained knowledge.
It is certainly an unexpected solution as when I explained to my diesel guy he was skeptical but accepting of the theory, which you have now proven.
Hopefully my new pump will arrive next week and I can have a fix too.
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Old 22-09-2012, 16:39   #45
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Quote:
Originally Posted by terrylad
Done. The saga is over. The engine runs like clockwork. The stalling problem was due to me installing the idle screw plate the wrong way around.

Lessons learned - the fuel pump was the problem, it has just a tiny wear spot on the flexible part of the diaphragm, coupled with a suspect flexible braided pipe from the fuel pump to the filter. I should have saved the IP rebuild until the last resort - I retrieved the old parts and they're perfect, no wear or muck on them at all. Oh, well.

So, spread the word on these symptoms - check the fuel pump asap. This episode has taken me all summer to get to the end. Fortunately I don't have deep seated problems on the engine, such as broken rings, lower end or even head gasket problems, but I guess its guaranteed to happen at some point in the future.....
All is well that ends well!

Glad it's working! 3GM30 is an excellent engine, simple design, lasts a long time!
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