Diesel Leaks Everywhere

[Mattyb]

Hi all

So my next problem with my new to me engine! I have a heap of diesel leaking from the fuel lines where the bolts go through. I figured it was just the copper washers needed replacing. I got some the right size internal diameter and a bit oversize externally but I didn't think this would be a problem and it hasn't slowed the leaks at all? Could it be the metal pipes need replacing? Also all of a sudden once I replaced them the engine wouldn't shut down! The usual method is to push the throttle leaver all the way back starving it out but now it doesn't stop it so I had to disconnect one of the fuel lines just to get it to stop!! Has anyone had this problem and is there some sort of device I can get to switch the engine off remotely etc? All advice much appreciated. Pics below show the connectors I am talking about.

[gjordan]

The ones on the fuel pump are called banjo nuts(or banjo connectors) and do tend to leak after they have been taken off and on many times. New copper washers may not do the trick. Sometimes polishing the top and bottom surface with a wet stone can make them seal better(dont let grit get into the lines. The other less common problem with banjo connectors is that the fuel line is silver soldered into the fitting and sometimes you get a tiny crack that is hard to see, but will weep fuel. The connectors and nuts(actually they are bolts) are not typical auto store items. Make friends with a diesel shop. They will be a big help._____Good Luck_____Grant.

[hellosailor]

I'm wondering if the new crush washers that you have (that's what they are called, because they deform and crush to make a seal, use once and discard) possibly aren't real crush washers, if they are too thick they won't do the job. If they weren't sold as "crush washers" they may not be right for the job.

"once I replaced them the engine wouldn't shut down! " Something else is wrong. Replacing the crush washers incorrectly would cause the fuel lines to leak fuel, or ingest air. Neither of those problems can cause engine run-on, so either it is coincidental, or you hit something else.

It is probably worth taking some time to try finding a good diesel shop, or a mechanic, and getting some advice from them. If you can bring a mechanic out with an understanding that he'll spend a certain amount of time, let you watch and show you what has to be done (like replacing those crush washers when you bleed air out of the fuel lines), that can be priceless.

[Ex-Calif]

If you are going to continue working on your engine yourself I suggest you get "Marine Diesel Engines" by NIgel Calder and a copy of the workshop manual for your engine. You can't really guess at this stuff and hope it comes out right all the time.

What engine do you have?

The copper washers are not really standard copper. The right parts are somewhat annealed and are soft. The banjo fitting has an "edge" that will crush the washer and form a seal. You need the right parts.

As far as shutting down my guess is either a rigging issue with the controls or the injector pump is failed or contaminated.

[Mattyb]

Thanks guys. I do have the workshop manual. I am thinking maybe u are correct and the washers I am using aren't doing their job. I live in a remote mining town so not many small engine places around and any help comes with an extreme dollar value. Forum is cheaper I will do some hunting around today for the correct washers. It would make sense that these ones are not crushing down as they are a bit bigger than the original ones. Hopefully once that is done and leaks stop I can bleed it thoroughly and the engine will cut off. I read last night a few places that air trapped can cause running issues including running at higher revs which it is now doing and won't shut off etc.

[Mattyb]

Oh and she is a yanmar2qm20 of unknown age. The po did very little maintenance as I am finding out more and more

[Mattyb]

Well it appears that no one in town has these washers. Am going to try reheating them and dropping in water to red often as one bloke suggested. See what happens

[hellosailor]

Matty, reheating (annealing, retempering) washers will NOT make them good again. The purpose of a crush washer, which in my limited experience usually looks like a piece of copper FOIL, is be be crushed and conform to fill gaps between imperfectmetal surfaces.

You would have to heat it up and then roll it between high pressure steel rollers to re-extrue the metal back into a flat foil sheet to make it good again. Annealing it will not make any difference, the thickness is still not going to be even.

Before you put any more time or money into it, I would really suggest contacting the engine maker, or an authorized dealer, and making sure that what you have are indeed the correct parts for that application. Just because you found them on the engine, doesn't mean the last guy used the right parts either.

Crush washers are a RFPITA and having already been in that play, I can only tell you that IF that's what you need, and IF you need the foil type, you want to order a whole box of them (matchbox sized box with one or two dozen in it) since the shipping and handling usually costs as much as the entire contents of a box.

They really are a RFPITA, but they serve a purpose. Diesel engines are like camels: All well and good, until they haul off and spit and kick at you.

[charliehows]

yeah i had a few problems with leaking fuel lines - real pita cos it usually happens when you're in the middle of a major shipping channel or similiar, i had 4 times my eng conked on me. In the end i went through the fuel lines from start to finish, used thread tape on all nut connections, new s/s hose clamps, all new rubber fuel hosing, annealed all copper washers on any banjos removed, replaced a couple of banjos with nut to hose conns. In essence, wherever you see any evidence of even the slightest bit of weeping fuel at any connection, you have to repair that connection - if it weeps fuel it will, at the most embarassing moment , leak air and stop the engine. I tried 3 different types of washer on the bleed valve at the inj. pump before settling on a polyethylene one - the others wouldnt seal, even though they didnt seem to let air in, still made me nervous til the conn. was bone dry.
good luck, its like bloody brain surgery, you have to be so meticulously clean in everything you touch, but once its done you can more or less forget it as a future source of problems.

[hellosailor]

" used thread tape on all nut connections,"
Be very careful about that. As the folks who make it will tell you, if that tape shreds off just a little bit, on the ends of the thread or inside the threads when it is being redone, the little shreds will migrate inside the fuel system and eventually hit the high pressure pump--where they will cause a very expensive pump failure. Only use thread tape on the far side of a fuel filter than can catch those shreds before they can jam into anything. Pipe dope sometimes is a better solution, other times nothing should be used and the fitting itself is supposed to compress and seal one way or another.

Plastic washers sound like they should work. I noticed that on cars "they" all use plastic washers on the oil drain plug these days, the old metal-on-metal just isn't being one anymore, use once and throw away.

[Mattyb]

Ok. Will contact the yanmar dealer in Perth and get them to send up the right fittings I think. Thanks for the help guys

[Ex-Calif]

I suspect you are in a tough location parts and delivery wise but having the right parts is pretty important.

Sometimes there is a groove on the banjo fitting, the copper washer has a couple of hole is it for the purpose of passing fuel across the groove.

The picture is the fuel return rail for my Volvo. The fuel passes the holes in the washer into a drilled passage in the groove and into the return tubes. You can see the groove in the banjo fitting is an integral part of the fuel return circuit.

If a non-drilled flat washer is used who knows where the pressure tries to go.

Here's a new washer and banjo fitting. I thought I had a couple of old washers around but I am sure I tossed them. These are not reusable items for me.

Although Volvo parts are expensive, I think these are like 13 cents.

[Mattyb]

Yeah it is very hard to source parts locally unless you own mining equipment! Those parts look quite different but will get them sent up. Not worried about money, just don't want to wait 2 weeks before I can get on the water again

[Mattyb]

Here is the washer that came off it and is the same as all the others just for reference

[Ex-Calif]

Yup - That washer is knackered.

Note the deformation and very sharp groove. Sometimes you can put a once used washer back on the same fitting and it will "find its groove." but swap it to a new fitting and the "new" groove is most likely to cross an old groove and you will never get it to seal.

Even if you anneal it.