Fuel filter leaking

[richardf]

I went to the boat for the first time for a couple of weeks this weekend and on opening the front doors was greeted with a strong smell of diesel. Investigaon showed that there was a lot of diesel lying in the bilges below the twin fuel filters - it drops into the V shaped area formed by the box under the engine and the swim.

 

The fuel filters were covered in oil - I wish I had a camera available, but didn't. The twin filter system has a one piece casting across the top and what appears to be one piece underneath. Above each filter is two bolts (and a tapping for another one, not used) - the fuel seems to be coming from there. I have tightened the small one in the centre up which I assume is pulling everything together, but it is difficult to know where the fuel is leaking from. Underneath there are two nylon (?) nuts - one of which will tighten up, the other won't. I'm not sure if there is actual leakage from here as the diesel is obviously running down to the lowest point before dripping into the bilge. It's an old engine (Kelvin P4) and there is always liquid under the engne, but I don't think there has ever been any in this particular spot before. I did top up with fuel last time I was down, maybe the additional head of diesel has shown up a leak? According to the guy who services my engine, it is a very difficult job to bleed after a filter change so I don't really want to strip it down if I can help it. Would it be possible to loosen off the middle bolt enough to get some sealant in there do you think? (any recommendations?) - if the centre bolt holds the filter together, what does the other one do - is it a bleed point? I did manage to tighten the centre bolt (didn't help) - but couldn't get anything on the other one.

Any thoughts would be most appreciated.

Cheers

Richard

[casper ghost]

- if the centre bolt holds the filter together, what does the other one do - is it a bleed point? I did manage to tighten the centre bolt (didn't help) - but couldn't get anything on the other one.

Any thoughts would be most appreciated.

Cheers

Richard

 

That would be my guess..

[RobinJ]

... Investigaon showed that there was a lot of diesel lying in the bilges below the twin fuel filters ... The twin filter system has a one piece casting across the top and what appears to be one piece underneath. Above each filter is two bolts (and a tapping for another one, not used) - the fuel seems to be coming from there. I have tightened the small one in the centre up which I assume is pulling everything together, but it is difficult to know where the fuel is leaking from.

Can't say I understand this filter, there are some designed for sea going vessels where you can change over without stopping the engine, this appears to be a dual series arrangement?

Most filters have a cartridge which fits between the top and bottom of the filter and the central bolt holds the two halves together. They are sealed with rubber rings top and bottom, with a dual system it will be even more important to make sure these are seated correctly, but I suspect overtightening may also crack the castings?

Underneath there are two nylon (?) nuts - one of which will tighten up, the other won't. I'm not sure if there is actual leakage from here as the diesel is obviously running down to the lowest point before dripping into the bilge.

There are usually drain valves at the bottom of a filter to remove water etc., these are fitted with rubber seals which can perish.

It's an old engine (Kelvin P4) and there is always liquid under the engne, but I don't think there has ever been any in this particular spot before. I did top up with fuel last time I was down, maybe the additional head of diesel has shown up a leak? According to the guy who services my engine, it is a very difficult job to bleed after a filter change so I don't really want to strip it down if I can help it.

Would not worry about that, as until the fuel leak is fixed, you not likely to run it anyway.

Turning of the fuel will help keep the tank full and give you a better chance of bleeding it afterwards!

[richardf]

Can't say I understand this filter, there are some designed for sea going vessels where you can change over without stopping the engine, this appears to be a dual series arrangement?

Most filters have a cartridge which fits between the top and bottom of the filter and the central bolt holds the two halves together. They are sealed with rubber rings top and bottom, with a dual system it will be even more important to make sure these are seated correctly, but I suspect overtightening may also crack the castings?

 

There are usually drain valves at the bottom of a filter to remove water etc., these are fitted with rubber seals which can perish.

 

Would not worry about that, as until the fuel leak is fixed, you not likely to run it anyway.

Turning of the fuel will help keep the tank full and give you a better chance of bleeding it afterwards!

 

By the sound of it then, I can loosen off the middle bolt enough to get some sealant underneath it and retighten.

 

The nylon nuts are a bit of a mystery - maybe the thread has stripped or something, it certainly won't tighten up. I do think the top bolt is the problem though

[Radio-Ga-Ga]

I don't know this filter either but the retaining (cenre bolt) usualy has a copper or soft alloy washer under it, the other may also. Better to replace the washers. Hold or prop the filter in place while you do it. (and turn off the fuel)