Replacement Of Fuel Injectors For Yanmar 3GM30

[Dragon Lady]

I pulled my pump out today, I can't find any holes but there are a few spots on the diaphragm that look a bit suspect but if you didn't know you would think it's OK.
Drained over 5 1/2 litres of oil out of the crankcase and it definitely has fuel in the oil so the pump must be shot.
Just waiting for the new pump to arrive from the UK.

[glynhome]

Glad to hear you are ship-shape again Terrylad.

I took your advice and called the engineers that were putting my engine back together again and told them to check the fuel lift pump, guess what, it had a crack in the diaphragm. They were going to put the whole thing together again with new rings, big ends etc and not look at the lift pump! I guess they thought that seized rings and a washing cylinder was enough reason for 6ltrs of liquid in the sump.

I spoke to the main UK distrubutor for Yanmar at the Southampton Boat Show this week and he didn't think the lift pump could cause a mix of fuel and lube, so there's a bit of denial (ignorance) circulating amongst the "professionals".

My engine is back in the boat and I spent 13hrs sailing her back from Newhaven (where she broke down) to Portsmouth on Friday night listening to every little noise while the engine was on, so far so good and starting is no longer a lottery.

I've been told to run her around half revs for the first ten hours with occassional short bursts at 2/3 revs. Sounds a bit vague but that's what I'm doing.

Total cost of this episode was $4,500.00 and my advice to all 3GM30 owners is inspect your lift pump at least every 5 years and get your injectors serviced every 3 or when smoking. Check your sump oil every trip and look for increases as well as decreases!

Some UK parts prices for you: Mixing Elbow Assembly $525, 3 Ring Sets $304, 3 Big end Brgs $118, Pump Fuel Feed $185, Injector and pump service $500.

Glyn

[glynhome]

One more thing - whenever I changed my engine oil over the past couple of years the oil went black very quickly. After the rebuild and 5hrs of running the oil was as good as new so I'm guessing that previously the oil was becomming contaminated.

So maybe another check, look out for quick contamination of sump oil.

Glyn

[terrylad]

Originally Posted by Dragon Lady

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.

Good luck with it. I hope that's the problem, because its such an easy fix.

Yanmar doesn't sell just the diaphragm, (which is worth about $2), only the whole unit, which cost me $80 locally.

You can open up the old pump easily to check for damage, and my diaphragm has a slightly perished section about 2mm long in the soft rubber next to the piston plate.

A strong note of thanks to everyone who contributed to this little adventure. Hopefully this experience may save others going to a lot of trouble unnecessarily. If it's as prolific as the Yanmar mechanic indicated, maybe this experience will save a lot of these engines as they get older. For cruisers, I'd advocate carrying a spare pump and I'd include a physical check of the original pump once a year with the engine filter change. Its such a simple job to pull the pump and open it up. Keep a stock of new banjo washers handy, though.

I understand that the 3GM30F series finished production in 2000, so they all should have a bit of age on them, even if it is shelf life.

Yes, I've still got PTSD every time the engine chuffs or changes note, but I'm hoping that will diminish over time.

[terrylad]

Originally Posted by Dragon Lady

I pulled my pump out today, I can't find any holes but there are a few spots on the diaphragm that look a bit suspect but if you didn't know you would think it's OK.
Drained over 5 1/2 litres of oil out of the crankcase and it definitely has fuel in the oil so the pump must be shot.
Just waiting for the new pump to arrive from the UK.

That's such great news (that it boils down to a simple fix). The crankcase should only have 2.9 litres of oil in it. You're lucky the piston rings escaped damage with all that fluid.

You just might have saved the engine......Good luck.

[DotDun]

Originally Posted by terrylad

I understand that the 3GM30F series finished production in 2000, so they all should have a bit of age on them, even if it is shelf life.

IIRC, the 3GM30 ran 1983-2005. Mine are 2002.

[Dragon Lady]

Just fitted a new lift pump and all the smoke has gone.
The engine runs like new again.
Very happy, thanks again to all those who shared their experience you saved me a lot of money.

[terrylad]

The engine bitchslapped me again. Turned out to be my own fault, of course.

While I was running it at the mooring, contemplating taking her out into a very brisk westerly in Narragansett Bay for a 'sea trial', the engine slowed and died while I cranked on the throttle......

I cursed a bit, after working all summer on this, and then checked fluids, water, oil - all good. Cranked the engine in decompression, no laboring - thank God. Then I went over my previous work and zero'd in on a new braided hose between the lift pump and the filter that had kinked up when I bent it to allow the banjo fittings to mate with the pump and the filter.

I found after removing it that there was ONE WAY to install it so that it didn't kink due to the braid winding orientation. Bled instantly with the handydandy squeeze pump and she fired up in 2 seconds.

Took me an hour from start to finish, and felt like my troubleshooting skills were well honed after working on the engine all summer. If that had happened last year I'd have been working on it for days, starting with the fuel tank and possibly ending with an injector pump rebuild!

I'm just glad the engine quit while I was still tethered to the mooring, and not in the middle of a hundred gin palaces in the harbor. Getting old age paranoia about soloing a 37' with no engine in a 20knot breeze in a busy harbor.

Now that summer's over, I have a huge amount of growth to scour off the hull before I can get some fall sailing in......Being your own crew sucks at times.

[gonesail]

lift pumps are cheap and easy to install. sounds like good practice to replace after 10 or 20 years.

[DotDun]

Originally Posted by terrylad

......Being your own crew sucks at times.

You have now graduated to PHD of 3GM30 fuel systems!

Congrats!

[olepedersen]

Yes we have all learned,1. we are not alone 2. we get slowly smarter 3.it is tough to do it alone.4. I am going to cheat and install an electric fuel pump before the racors,and just let the yanmar pump sit and pump air. Perhaps I dont get a PHD but it should work. Ole

[robertsapp]

I'd like to jump in with a couple of related questions if I may. First, the braided fuel hose that runs from the lift pump to the engine filter. Mine started weeping a little. I wasn't completely sure whether it was fuel seeping out or if it was a little bit of oil that had dripped down onto the hose from a small leak I have at the aft end of the injection pump. I decided to replace the hose just in case. Well, my local Yanmar dealer says he can't find it. Supposedly all he can get is one made of solid metal tubing. This just doesn't sound right to me. I thought I read somewhere that these engines originally had a solid pipe, but Yanmar switched to the flexible braided tube to solve some sort of problem they were having. Does anyone have any information on this part or its availability?

Second question. My engine is a '95. I bought the boat in 2009. I doubt the previous owner ever touched the injectors, because that's the type of guy he was. He allowed a small seawater leak from the vented loop to drip on the cylinder head for years and never did anything about it. I'd like to remove and replace the injectors, but my manual shows that there are five or six little parts below the injector. I'm terrified that the injectors are corrosion welded to the head, and if I try to blow them out with compression, I might dislodge those little parts below the injectors and never get things right again. What's the best way to proceed?

[ggray]

Thanks! That might be what I need.

Originally Posted by Dsanduril

See if your local diesel mechanic will loan you his slide hammer?

I can't count the number of hours I've spend trying to get stuck injectors out using the tools I own, the right tool took about 30 seconds.

The slide hammer has an adapter (or set of adapters) that screw onto the top of the injector. A couple of strokes are usually all it takes to get the thing budging.

The shop where I take the injectors for testing/rebuilding is more than happy to loan their's out for a couple of hours.

[terrylad]

Hi Robertsapp, re your braided hose linking the fuel pump and the fuel filter -- I had no trouble locating a part source and it was delivered to the local dealer (Oldport Marine in Newport) in a day or two at a cost of $24. They also supplied banjo fitting washers for both ends for about $4. They also said that the original solid pipe fitting was no longer supplied.

I was lucky with pulling my injectors, it just took a slight turn using a wrench on the injector flat sides to release each one after the fuel lines and return pipe had been removed, along with the intake shroud. The injectors looked pretty good, so I didn't try to remove the washers and combustion caps lodged down the hole. I'd try that first. Any stuck ones I'd be inclined to INDIVIDUALLY ease the holding clamps a few turns on each nut and

[terrylad]

...Robertsapp reply continued....
Sorry, the previous reply jumped into the forum format for some reason.
So, if one or more injectors are bound up, I'd ease the injector clamp by one or two turns on the holding nuts on one and use the decompression lever(s) on the other(s) and crank the engine VERY briefly. (A friend of mine has a hole in the deck of his Sea Wolf ketch where the injector in his Westerbeke fired off like a rocket. It missed his head...)

So, yes, if you can get hold of a slide hammer, great.

Incidentally, I'd replace all the banjo fitting washers with new ones as a matter of course. They're cheap and can eliminate potential problems.