Yanmar Diesel Leak - with picture!

Zagato

Zagato

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Whilst the boat was in storage I had a very small diesel leak. The engine was serviced, boat launched and it ran OK without a leak for 30 minutes to get onto the mooring. Whilst motoring yesterday to fill up with diesel the leak returned, drips every second or so. It seems to be coming from one of the 2 scews on top of this filter/bowl (not sure what it's called). It's a Yanmar 2GM20. Trying to avoid a £150 call out fee :rolleyes: Thanks, It may be coming from somewhere else of course but this looks the right place and it's covered in diesel!

IMG_3074_zps0c6c188f.jpg
 
The screw on the right in your photo is the air bleed screw. Presumably this will have been disturbed during servicing. Try tightening it to stop the leak. But be careful not to overtighten it, as it's possible to strip the thread, meaning you'll have to replace the filter head!
 
pvb said:
The screw on the right in your photo is the air bleed screw. Presumably this will have been disturbed during servicing. Try tightening it to stop the leak. But be careful not to overtighten it, as it's possible to strip the thread, meaning you'll have to replace the filter head!
Click to expand...

Or bleed from the banjo thereafter with an oversize set screw permanently forced into the bleed hole. (Ask me how I know!)
N
 
Yep, it's the bleed screw. Best to operate it with a ring spanner or socket rather than a screwdriver, as they seem to be unnecessarily soft and prone to stripping the slot.

It would be a good idea to learn about the bleed points and other basic things on your engine, as paying the £150 may not be an option at sea.

Pete
 
Advisable to replace the copper washer with a new one or anneal (soften) the existing one. To anneal it heat it on your gas stove till cherry red for a few seconds and cool, you can drop it into water.
 
If the filter has been changed check that the locking ring is tight as that is another potential source of air getting in.
 
I'm not a great believer in courses but with your obvious lack of experience of things diesel I suggest it would be worthwhile you doing a basic diesel engine maintenance course. You will be able to service your own engine and manage problems at sea, it will save you a fortune in bills and possibly having to call for help.
 
Drips every second or so seems a lot for a leak from the bleed screw. There was a problem with the rubber o-ring inside these Yanmar filters. The problem was the diameter of the ring was too small and the knurled ring was reaching the end of the travel before the filter was sealing against the ring. Solved by replacing with a wider o-ring.
 
savageseadog said:
I'm not a great believer in courses but with your obvious lack of experience of things diesel I suggest it would be worthwhile you doing a basic diesel engine maintenance course. You will be able to service your own engine and manage problems at sea, it will save you a fortune in bills and possibly having to call for help.
Click to expand...

Best way to do that is pay an engineer to spend a few hours with you on your own engine.
 
Spyro said:
Drips every second or so seems a lot for a leak from the bleed screw. There was a problem with the rubber o-ring inside these Yanmar filters. The problem was the diameter of the ring was too small and the knurled ring was reaching the end of the travel before the filter was sealing against the ring. Solved by replacing with a wider o-ring.
Click to expand...

Not if under pressure from the lift pump
 
If the bleed screw is slack and you aldready have diesel around the place why not bleed the system -its something you should know how to do and is dead easy.
The only hardish part is finding the priming pump - the rest is easy. The priming pump is on the left hand side of the engine when viewed from the direction of your photo. It is a small push down tab on the fuel injection pump on the side away from the fuel filter.
Open the bleed screw a little then press the pump up and down (it has a spring return.) Diesel will come out of the bleed screw and you can stop pumping when there are no air bubbles coming out
It is always handy to have few plastic containers to collect the diesel drips (e.g cut down plastic bottles)

It would not hurt to try pumping the priming pump to give an inication of whether you have solved the leak
 
New, annealed washer every time ( Yanmar 3gm, same component). Just buy em by the box!
Another trick is to double up on em plus +1 on what Tranona says re bowl
 
Sometimes it is difficult to see where the actual leak comes from.
If you get some kitchen roll or soft toilet tissue use some to wipe the whole area dry then place a separate piece around each of the likely spots
You can soon see which bit is stained
Having sorted the leak place a larger piece under the whole bowl & you will see after a few hours or a day if there are still some leaks
You do need to wipe everything dry first
 
Just had the same issue with my 3GM.
Replacing the copper washers on the banjo and bleed point was the solution.
As Blueboatman states, grab a handful to keep on board.
 
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