Yanmar 2GM20 - fuel weep

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fireball

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I have a Yanmar 2GM20 which has been smelling a bit recently ... I've traced the fault down to a slow drip of water from the secondary fuel fillter - the one just after the lift pump on the engine - this is probably from when we changed the filter and the bowl hasn't fitted properly again ...

I've tried just tightening it up - tapped round with a flat blade and light hammer, but this hasn't stopped the leak completely ....

It's a bit of a PITA - I don't want to remove the bowl unless I really have to because I then have to bleed the engine through again ....

Has anyone else had similar problem and resolved without removing it?
 
I had a similar problem in that I couldnt really get the threaded collar tight enough by hand to stop the slight weep.
I put a large jubilee clip around it then lightly tapped the screw head on the jubilee clip with a screw driver and hammer to tighten it about 1/8th of a turn. It worked. Left the clip on to use on later removal.
 
I did wonder - the drips and weep is down the back where I can't really see ... I'd been through and tightened everything I thought I could - so it could be the washer ... anyone know what size or do I have to look in the workshop manual .... /forums/images/graemlins/blush.gif
 
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I'd been through and tightened everything I thought I could - so it could be the washer ... anyone know what size or do I have to look in the workshop manual .... /forums/images/graemlins/blush.gif

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The larger of the two bolts is M8, but unfortunately I don't know the size of the smaller (bleed screw) one. I doubt it's in the workshop manual, either.

Andy
 
Your overtightening just may be counterproductive, unless you watch the torque. I had a similar fuel leak from the secondary filter, same engine. The bolt is an integral part of the fuel system, with its own fuel channel. This bolt (NOT the bleed screw) had at some stage been overtightened and had completely stripped the thread from body of the filter, leaving no real alternative (short of very skilled engineering) but to replace the whole filter body: a simple but expensive exercise.
I hope its just the copper washer in your case....
 
There's a limit to how much you can tighten the ring - it seats on a rubber O ring, which (from memory) is around 40 x 1.5mm, ie very thin. I replaced mine at the beginning of the season (bought it from Marine Power, Bursleden via their web site). I haven't found one yet, but I'd prefer to fit a slightly fatter one, say 2mm dia.
As for the copper washers on the bleed screws, just heat them up to red heat and dump them in a mug of cold water - then re-use them. If they are really shot, most motor factors can sell you a few for a few pence.
 
The right thing to do is to remove the filter again and check the o ring, assuming that you have tightened the bolts on top reasonably but as correctly pointed out above definitely do not overtighten. Its no big deal to bleed the engine i usually don't bother with the hand pump. Instead I loosen the bleed screw and start the engine letting air bubbles out until the diesel runs clear. Small clean up in the bilge after which you can make easier by pre-emptive strike with some absorbing material.
 
was going to say exactly the same thing, mine was always leaking from the bowl, replaced the o-ring with new yanmar one, even tried two. in the eng i put a 2.5mm one on from o-ring kit from ebay. worked a treat.

steve
 
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