Yanmar 2GM injection pump leaking between the delivery valve holder and body after possible overtightening the former?

[vas]

afternoon all,

a couple of weeks ago (and for no apparent reason-just plain stupidity!) decided to check the pipes from the injection pump to the injectors.
Undid a bit the (easy) front one (i.e. cyl 2) pipe (17mm nut) and thought it was a good idea to try and tighten the 19mm nut under it (in the diagram below it's item 1: delivery valve holder)
Amazing it did turn maybe 10-15 degrees. Happy, tightened the steel pipe (17mm nut) and started the engine.
Run fine, only to find that a puddle of diesel started gather under the engine, on close inspection it came out of the joint between the injection pump body and this #1 deliver valve holder.
Tried various things, undo it to the point it was before (approx), tighten it more, etc no luck, leaking!
Engine does manage 3k ish rpm which is the revs it has to run the generator.
Looking at the following diagram it seems to me that I've stupidly crushed/damaged the #2 item o-ring (assuming it is a rubber o-ring and not something else!).



Question to knowledgeable ppl in here:
is it a straight forward job to undo the 17mm nut of the steel pipe to the second injector, remove it completely (ok undo the injector side and remove the mid mount) and then undo this #1 thing and fish the o-ring and replace?
what happens with items #3 - #8???
do they stay in there happily aligned waiting for the delivery valve holder to come crushing onto them, I very much doubt it!

Am I missing something?

You'll probably suggest I better remove the injection pump which I'd like to avoid atm as the engine is an F, and I'm pretty sure I have to remove the heat exchanger before I proceed (no clearance on top of the pump...)
So any tricks or other ideas on why it started leaking once I overtightened it?

cheers

V

 

[black mercury]

You could have crushed the washer, which is gasket no. 8 on the diagram.
You don't need to remove the pump. Unscrew the delivery valve holder, the valve should sit in the injection pump. You simply need a bit of common sense and care. You can lift out the valve, keeping everything together. You may need a small prick or magnet to remove the washer. It's more complicated than it looks, unless you drop it into the bilge!
Any diesel shop should get you the parts, take a note of the pump number on the plate.

 

[vas]

thanks black mercury!

I hope you meant "it's less complicated than it looks" as it doesn't look that complicated but granted I need some needle pliers, or watchmakers' kit to remove them. It's also placed in an elevated spot so not easy to see from the top.
I'll give it a go in the afternoon when I get there and post my findings!

cheers

V.

 

[black mercury]

Sorry, yes meant LESS complicated than it looks!

 

[vas]

ΟΚ,
Managed to remove up to #6, 7 and 8 is impossible to remove without taking the pump out.
Oring is rather tired, hope that replacing it tomorrow will do the trick. Lots of surface rust, easy to remove (and not throw in the pump!) so done that.
Reasonably confident it's going to be it. We shall see.

Cheers

V.

 

[Bilgediver]

If you take the pump out then lift it slowly carefully and keep it level till you have got hold of the bush on the side pin of item 10. When replacing the pump make sure that the bush is on the pin and that it sits correctly in the forked lever or you will get no fuel.

You should be able to get that washer out with something like a steel scriber.

 

[vas]

If you take the pump out then lift it slowly carefully and keep it level till you have got hold of the bush on the side pin of item 10. When replacing the pump make sure that the bush is on the pin and that it sits correctly in the forked lever or you will get no fuel.

that's going to be the last resort as it means I have to remove coolant pipes, heat exchanger, etc.
So going for the easy solution.
I see that on a 1GM things are a bit easier as you can see and get the forked lever in place. Seems that on 2 and 3GMs you pray when you put the pump back in. Wonder if there is a way to know that you got the fork in without reassembling the lot and firing the engine up!
If there is a failsafe way, I could possibly give it a go if o-ring fails, even at lifting the pump for two inches and tilting it outwards so I can fish the two pieces out...

You should be able to get that washer out with something like a steel scriber.

it's so tight, managed to get #6 out using a big thick needle bent 90deg at the end.
should get another and try bending it v.little and try to fish it, thing is cannot see what I'm doing so it's feel only and it doesn't help much...


V.

 

[Tamar]

Just had mine done on my Perkins. Number 8 I believe on the diagram. Mine were rubber o rings. No need to remove the pump, just the injection pipe. The thing on the pump just unscrews and the o ring is underneath.

 

[vas]

Just had mine done on my Perkins. Number 8 I believe on the diagram. Mine were rubber o rings. No need to remove the pump, just the injection pipe. The thing on the pump just unscrews and the o ring is underneath.

hi,

well, #5 says gasket and was a nice copper washer. #8 also says gasket, so I hope it's also a nice copper washer.
#2 is the one just under the lip on the #1 delivery valve holder hence me hoping that's going to be it.

Out of curiosity, did yours leak, and if so, did you do something to it, or just started leaking?

cheers

V.

 

[Bilgediver]

Just had mine done on my Perkins. Number 8 I believe on the diagram. Mine were rubber o rings. No need to remove the pump, just the injection pipe. The thing on the pump just unscrews and the o ring is underneath.

Usually there are soft copper washers. They work harden. I rarely replace them I re anneal them so they are soft again. Just need to heat to red heat and drop in cold water and good for another 20 years so long as no obvious damage. I sailed with a tramp company and money was tight

 

[Tamar]

hi,

well, #5 says gasket and was a nice copper washer. #8 also says gasket, so I hope it's also a nice copper washer.
#2 is the one just under the lip on the #1 delivery valve holder hence me hoping that's going to be it.

Out of curiosity, did yours leak, and if so, did you do something to it, or just started leaking?

cheers

V.

Hi yes mine just started leaking a bit so I hung a tin underneath the pump to catch the diesel, to start the leak wasn't so bad, but after around 6 weeks it would leak pretty bad.
I gave the job to the marina engineering dept, they said they changed the rubber o rings. Common problem apparently. Perhaps they meant washers or perhaps my Perkins pump is different.

 

[vas]

belated update,

got new o-rings (3 just in case for 50eurocent), fitted the one on the cyl 2 that I'd messed about, everything tightened fine.
Tried starting, took me a good while bleeding the lot, eventually started, not exceptionally happy and not revving to 3krpm where the governor was stuck but more like 2.7k.
Left it running to check for leaks, no leaks.

Tried starting it a couple of days later nada, needs bleeding again, didn't bother, I can live without the generator for a week or two it seems unless it gets cloudy and I cannot run the watermaker from the solar!

Anyway, plan to have another go in the next few days, problem to me seemd to be that the diesel spitting out of the injector side nut on cyl2 (the one I messed with) is seeming much less in quantity and power of flowing. As if it's restricted somehow. Not keen to take the pump apart in the middle of nowhere, not much of a point, I'll try removing and reseating the bits I messed with again and bleed the system again and report back.
Anything I may be missing? other than dirt falling in and messing with the pump that I'm pretty sure I've not done!
Didn't anneal the copper washer I got out, could do next time, looked in decent shape tbh.

cheers

V.

 

[vas]

and another update,

loosening the seawater pump pulley (no need to mess the impeller nor flood the engine), cranking it's balls off with the cyl2 decompressed, it eventually starts firing on cy1, drop decomp on cyl2, keeps on slowly and eventually after a minute or so works. Definitely wasn't like that before messing with it!
Run the generator on lowish load, it managed with a bit of tinkering to run at 3k rpm and charge the batteries. Wouldn't run the 2kw watermaker at the same time (3kw load on a 8kw generator...)

Definitely down on power - low on fuel on cyl2. Tried bleeding it, no point if engine runs for half an hour!
Plan is to remove the pump get it to a specialist and prey before refitting it so it drops in the right spot so I have fuel.
Any trick to match the fork on a 2GM much appreciated.
Sort of removing crank pulley and removing the whole ali "face" of the engine that is.

V.

 

[black mercury]

If you remove the four nuts holding pump down it will spring up slightly, gently lift it until you can see or feel with a small screwdriver the rack. It needs to be moved to a particular position before it clears the block. Sometimes it's easier to remove the plate where the throttle lever is to make sure it's in the correct position especially when reinstalling it, but can be done without. Under no circumstances try to prise the pump out with a lever, if it doesn't want to come the rack is in the wrong position.
Before removing are you sure the pump is bleed at the pump, the parts you removed are back in the same order and everything was scrupulously clean?
If you can actually see the difference in fuel being delivered to the two cylinders then, yes it must be a problem within the pump. Highly unlikely but maybe the control sleeve has jumped a tooth when you tightened the valve. How tight did you tighten it? There is a torque value for tightening the valve holder.

 

[vas]

thanks for the instructions bm, happy to remove the throttle lever plate if it helps refitting it!
yes pump is bled long enough (don't forget I managed to get the engine running for half an hour, can it still have air in? I doubt!)
yes all cleaned and all back in the same order (don't think it's easy to assemble it differently tbh)
Last point you make is slightly confusing, as there's only one control sleeve which is unrelated to the two injector points on top, right?
How could overtightening something on top, affect something that bolts on (I guess) underneath?
I do have torque wrench which I cannot fit in there as I need either open sockets and v.narrow ones as the two injector outlets on top of the pump are way too close for normal sockets. I haven't gone crazy at it, but it's not lightly tightened either.
I wonder if following the reassembly there's an internal leak in the hp pump and not enough fuel finds it's way to the cyl#2 outlet. It's definitely less than what cyl1 gets. I could get temp copper pipes flared and with the right size nuts, and bolt them in and measure the output after say 50cranks in two separate containers, but it's getting difficult and edging silly. Got decent diesel pump specialists in Volos I could get it to them and be done with I recon.

of course if it's something easy I could check, I'd like to do it!

cheers

V.

 

[black mercury]

It sounds as if you haven't overtightened anything and it shouldn't upset the internals of the pump anyway, but I am trying to work out what could have happened. In the diagram the control sleeve has little teeth that the rack moves to increase or decrease the fuel. A bit similar to rack and pinion steering. The control sleeve moves the barrel in relation to the pumping element. If everything was OK before trying to fix the leak then something has been upset, it shouldn't have been, but stranger things have happened. Each cylinder has it's own pumping barrel and control sleeve, all connected by the rack. Wear to the pumping element can give the same reduction of fuel but that would be over a long period of time.
I have seen the smaller 1gm run with reduced power and run badly at higher throttle settings but would happily idle. It was caused by air at the injection pump. Opened the bleed screw at the pump with engine running and all was well after a few spits of air came out, so it can happen even if engine has been running. But it sounds as if you have been bleeding it quite a few times so it should be well bleed by now, although it might be worth opening the bleed screw at the injection pump with the engine running, wouldn't take much to try. But yes, does seem the pump will have to come off to see what has gone wrong.

 

[vas]

thanks again bm,

when you mention bleed screw on the pump what do you mean?
Mine has a simple banjo on the inlet from the main yanmar filter (that was another cause for concern only this season sorted it for good so that it doesn't leak air in the system...)

I can undo the cyl#2 19mm nut of the metal (copper, ss dunno what's it) pipe going to the injector (you know the one that bolts on the delivery valve holder #1 on the diagram on the OP), is that what you mean?
I'm afraid that undoing the high pressure pump inlet banjo I'm going to introduce lots of air in the pump and kill it, no?

cheers

V

 

[black mercury]

There's usually a smaller bleed screw on that banjo bolt (the banjo on the pipe coming from filter housing) on the injection pump that you use a 10mm spanner to undo but maybe you don't have that. Anyway, you need to make sure no air is in the pump and the only way then is to loosen that banjo bolt. Either use the lever on the lift pump or you can open while it's running, don't worry about letting in air as it's under slight pressure from the lift pump and it's only for a couple of seconds.
Before going any further you must make sure the pump is bled at this banjo, if you haven't already done so.
No, leave the delivery valve connections alone. If you need to you can crack open the injection pipe union up at the injector when cranking over the engine.

 

[vas]

update,

back in home port, went and asked the mechanic that rebuilt the motor 2yrs ago, explained to me that what I did was stupid (no news there...) and that the delivery valve holder (1) via the spring (3) presses the delivery valve (4) to regulate quantity and at what pressure (if I got that right) diesel goes to the injector.
He explained that normally the delivery valve holder is placed and secured with threadlock when high pressure pump is tuned, so you don't ever touch it!
anyway, he suggested I slowly start screwing the deliver valve holder a few degrees at a time until the thing works, if I fail, take the pump to the pump specialist in Volos.
So thought I'd have a go, noticed that flow was little on cyl2 (undid the injector pipe half a turn) turned it say 10deg, flow was better, a bit more etc.
Eventually undid the "good" cyl1 injector pipe so I could compare flow/pressure and reached a point that looked similar. Tried starting, it runs and generator is happy to dump 50A to the batteries and at the same time run the 2kw watermaker without dropping revs and going out of limits for 240V. So looks like success!
will try again to start it up from stone cold, if it fires up in a similar manner as it did before, I'll call it sorted (and wont touch a delivery valve holder again in my life
if it is hesitant in starting, I'll try tightening the delivery valve holder a bit more and see where I get.

cheers
V.

 

[vas]

and a final update on this saga...

a week later, engine wouldn't start no mater what, so took the plunge and removed the front pulley, front casing of the engine together with the high pressure pump (loose and lifted a bit). The reason is that I already had a leak on the accel shaft and didn't want to take the whole exhaust manifold with heat exchanger etc out (no clearance to remove pump else)
anyway, 10euro later the local pump shop removed both pump mechanisms, checked and changed a couple of copper washers and o-rings, put it all back together, tested it and gave it back to me. His take was that by tightening the 19mm nut I unset the internals and messed with fueling. Undoing the nut wouldn't restore the damage, had to take everything apart and fit them again at the right orientation.

anyway, just back from the boat where I refitted the lot, bled and fired the engine. Sure enough works fine, once I get the seawater pump back in place I can run it for an hour and see how it goes (should be OK)

cheers

V.