diesel drip under engine

[hector]

So... in the course of various investigations for the last question I asked, I now think there is a slow diesel drip under the engine which I only noticed (heard) after I switched the engine off, and I am fairly sure that...

 

1. It slowed to a stop as the engine cooled

2. That it *wasn't* coming from what the last thread identified as my fuel return pipe. It seemed to be coming from nearer the gearbox end, below the sump pump on my Barrus Shire 40 (04 build). However it's a trad stern boat with a compartmentalised bilge and so it's really difficult to see what's going on around the engine anywhere below half way down.

 

Engine sounds a little farty and rhythmical out the exhaust to me, but I have been listening to it a lot, and just had the fuel cleaned so it's possible I am either just listening too hard or I have got used to the sound of dirty/wet fuel...

 

If it's not the fuel return, what are some other problems? It's not pouring out, as there's only a few mm under the engine in a puddle to one side which I've only just properly noticed (it can often be damp down there, and only a torch revealed a pinky colour...)

 

I'm about 5 miles out from our base marina with more skilled friends and mechanics, or a couple of miles from a usable mooring spot, so I suppose the other question is can I proceed up the canal with caution, or is there a possible cause of this that means I should definitely stay put? The engine is running, and doesn't seem to be spluttering or smoky or overheating or anything else.

 

One (only one) of the battery lights briefly came on and went off again earlier today. Irrelevant?

 

Thanks,

Hector.

 

 

[Tony Brooks]

1. Generic advice. I think that when you stop the engine the low pressure part of the fuel system will still be pressurised by the lift pump, that will gradually drop if you have a leak, so that would explain why is stops after a bit. I would start looking between the lift pump, filter, and injection pump. On what you say you can probably carry on cruising while you identify and solve the leak.

 

2. Depends upon what you mean by "came on" and what electrical equipment you have on board. If you have solar and well charged batteries, it can cause the alternator to shut down until an electrical load is put on the batteries. I would suggest a watching brief until you get more idea about the specific circumstances that brought it on.

 

PS. thanks for starting another shared, that was very thoughtful of you. It will save confusion and help others.

[hector]

Thanks Tony, I'll head slowly up the canal. I've tracked down an available engineer a few miles away.

 

I'll monitor the fuel and batteries, but yes I've often suspected the lights and alarm sometimes come on when we are heading out from being on shoreline for a while, and fully charged. We have no solar but the inverter was off so batts were reading 14.3 and not really any load on them. Maybe the fridge came back on!

 

PS Yes, I've been on multi-issue threads on other forums... total nightmare, my original one was bad enough!

[Tony Brooks]

21 minutes ago, hector said:

Maybe the fridge came back on!

 

That is a perfectly valid explanation. If it does, it again try to turn the water pump/tap on and see if it immediately goes out. If it does, then it probably is very well charge batteries.

[BEngo]

As far as the leak is concerned bog roll or kitchen roll is your friend.  Wrap a strip of it round each of the joints on around and under the engine, before the fuel injection pump.

 

Go boating.  When you have shut down and the drip should have stopped, look at the paper strips for the one that is now orange.  That is the fitting that is leaking.

 

N

[Peugeot 106]

Blue roll is best. Any leaks are immediately obvious

 

 

[Ex Brummie]

White kitchen or toilet roll will show the pink up best and for a small leak can pick up a leak quicker than coarser blue roll, and if you haven't got blue roll, then it's infinitely better.

In my working life, servicing oil boilers, I used to carry blue roll for mopping up as it kept its texture better, but always used kitchen for leak detection.

[BEngo]

Big Blue Bog Roll is great stuff but, to the inexperienced,  not very discriminating between oil, red diesel and water/antifreeze.  White paper roll is clearer.

I also suspect that nearly all boats will have kitchen roll and /or bog roll, but not many will have BBBR.

N

[Peugeot 106]

1 hour ago, Ex Brummie said:

White kitchen or toilet roll will show the pink up best and for a small leak can pick up a leak quicker than coarser blue roll, and if you haven't got blue roll, then it's infinitely better.

In my working life, servicing oil boilers, I used to carry blue roll for mopping up as it kept its texture better, but always used kitchen for leak detection.

 

1 hour ago, BEngo said:

Big Blue Bog Roll is great stuff but, to the inexperienced,  not very discriminating between oil, red diesel and water/antifreeze.  White paper roll is clearer.

I also suspect that nearly all boats will have kitchen roll and /or bog roll, but not many will have BBBR.

N

Two good points from people with more experience than me. I’ve had various leaks and found blue to be very good for oil, water and fuel leaks. I’ve tried dye in oil to find oil leaks and kitchen towel but found blue paper best of all. Suggest you try both then it gives you two stabs I suppose it also depends on how good your eyes are

[Francis Herne]

Perhaps a silly question, but are you sure it is diesel?

 

Some gearboxes take ATF which is pink and looks similar to red diesel at a glance.

 

Asking because (a) you say it's near the gearbox (b) my own is currently dripping a small amount of ATF which I need to look into.

Edited August 10, 2023 by Francis Herne