Fuel Filters - advice for replacing (canaline 42)

[Johny London]

I wonder if anyone could kindly tell me a good procedure for changing my fuel filters?

 

I've had a good old google, watched a few vids but didn't find anything specific to my engine and the manual is not too detailed.

 

As I understand it so far - there is a primary and secondary? I've only been supplied with one filter from when I asked for "everything" at a chandlers. I'm concerned about getting air in the system and not being able to restart - as I have no other means for hot water/electric it would be pretty inconvenient.

 

Sorry if its a dumb question - I've mastered the oils/air and so on

[dmr]

There are usually two filters on a boat. The second is on the engine so is part of the engine as supplied and this will be the one supplied by the chandlers for your engine.

The first filter will most likely be fixed to the boat and was fitted by the boat builder, so this can't be identified by the chandler if they only know the model of your engine. If you look it should have a number on it.

 

Exact bleeding procedure depends on your engine, they are all a bit different. You could maybe pay someone to do it and teach you at the same time.

To minimise air problems I normally change the first filter, disconnect an appropriate fuel line and pump all the air out then run the engine. I then do the second filter and bleed that. This way if something does go wrong I have a good idea where the problem is.

 

............Dave

[Scholar Gypsy]

As far as I can see from the manual there can be some variation of installation. So you really need to trace the pipework from the fuel tank and see what you come to. On my boat - a non-standard installation, and not a Canaline engine - there is a primary filter, then the fuel pump (which has its own small filter inside, not really needed) and then the secondary filter that is attached to the engine. Then is a bleed point on the secondary filter and one on the inlet to the high pressure injection pump. (There is also a bleed point on the primary filter but opening that will only result in air being sucked into the system, as it is upstream of the pump).

 

My point here is that you really need to understand how the various components are installed on your boat and what they do, in order to work out how to replace the filters and how to bleed the system.

 

When I did the RYA course, the most entertaining part was the instructor saying it was important not to overtighten the fuel filter when reassembling it, otherwise it might leak. Ditto if you undertighten it. In response to the obvious question the answer was "experience". Failing that you can try to get a feel of how tight the central bolt is when you undo it..

 

Hope that helps ....

 

PS I find a dentist's mirror helpful to check that the upper O rings are properly seated - as well as touch.

Edited February 15, 2017 by Scholar Gypsy

[Tony Brooks]

I will do what I can to help but I have never worked on one of those engines.

 

First of all the ENGINE only has one fuel filter, probably the one you were supplied with. Good practice would also fit some form of water trap between the fuel tank and the engine. If the water trap is an agglomerator (all filters will agglomerate water) then it will contain a replaceable filter. If it is some other type of water trap it may have nothing more in it than space and an inverted cone or a washable/cleanable element. Many boast do not have such a water trap so you need to follow the main fuel feed pipe from the tank to see if you have one or not. If you do and can send a photo we may then be able to tell you how to deal with it.

 

I am sure the engine filter is a spin on type and that the engine is self bleeding so this is the procedure.

 

1. make sure the start battery is well charged (it normally is).

 

2. Take the new filter and fill with CLEAN diesel that you bought for the job. Road diesel is fine.

 

3. Put a smear of engine oil around the rubber seal(s) on the top of the filter and stand upright to one side.

 

4. Remove the old filter and make sure all the rubber seals come off as well, do not inadvertently leave a seal in place.

 

5. If the new filter does not have a centre seal but the old one does change the seal over.

 

6 Upend the old filter into an old plastic food tub to drain.

 

7. Screw the new filter onto the engine and once the seal touches the filter head tighten it a further half to three quarters of a turn BY HAND.

 

8. Start engine, it will take a few goes and may stall if any air gets into the injector pump, but just spin it a bit more.

 

9. Shake the remaining "stuff" out of the old filter into the tub and inspect for signs of Jelly (bug) hardish black flecks (degrading fuel hoses) or rusty water.

 

10 Clean up, check for leaks and try a few more starts.

 

 

PS - I do not think your fuel filter will have a centre bolt but if the primary filter is an agglomerator it might. It may also have four seals for you to get in the right place. Hence my wanting to know what it is if you have one.

Edited February 15, 2017 by Tony Brooks

[Graham and Jo]

We have a Canaline engine on Accessible Boating's holiday boat. An interesting quirk is that the filter has, what appears to be, a drain plug in the bottom. This is not supplied with the new filter so has to be swapped from the old to the new ( after removing the old one and emptying it. The system is self bleeding but there is a little device on top of the filter to get it going, just push it down a few times.

 

We also have to turn off the feed and return from the tank to stop it emptying into the engine bay when the filter is removed.

 

Cheers Graham

[Paringa]

Can't add a lot to the previous posts and that very helpful last one other than to close any fuel shut off valves before you start so that the diesel in the pipes doesn't run back to the tank...remembering to turn them back on before starting!

 

Good tip on filling the main filter, saves a lot of cranking.

 

Beaten to it

Edited February 15, 2017 by Paringa

[Quaysider]

I've got a canal line 42 on Ellis - it's very easy to change the filter... as already said, remember to save the nut on the bottom of the old one.

 

Once done you can either undo the bleed nut on the top of the assembly and then manually prime the little circular pump on top of it until diesel comes out then re-tighten or rely on the "self priming" engine to do it, itself on cranking...

 

this might help http://narrowboatellis.blogspot.co.uk/2016/12/50-hour-oilfilter-change.html

 

If I can do it - anyone can.

[b0atman]

my engine an Isuzu self primes by turning ignition key to pos 1 and you hear the diesel flowing back into the fuel tank through the spill back line .

[Johny London]

Just to complete this thread should anyone be browsing for info in the future...

I turned off the fuel line and removed the external fuel filter first. It has a nut under it (presumably for bleeding?) but you just need to undo the top nut and it all pulls apart. The new filter came with two large O rings, one goes between it and the bottom plate (that holds the filter in place) and one right up in the top part of the filter housing. This one is difficult to see, easy to forget (you could end up putting another ring over it!) and a bit tricky to remove - I worried it out with a screwdriver. There is a small O ring that lives on a shaft under the top housing - once again it's hard to see (I used the mirror again) and very tricky to remove (I got it out with a knife, somewhat destructively). There was a rubber seal between the drain plug and bottom plate - had to stick with that as it is not a ring and nothing was in with the new filter like that). There is also a rubber seal (O ring if I remember) under the top nut. Anyway - I held the new filter in place onto the bottom plate (with new seal in place) and filled it with diesel. I pushed the whole thing up under the top plate of the filter assembly and got the nut in by hand, then tightened up a bit... hopefully not too much. The engine fired and ran perfectly but I wondered if there was air still somewhere between that filter and the engine, waiting to cause problems.

Next I tackled the engine filter. It was tough to get undone and I didn't want to break it... just in case. The new one came without a metal plug in the bottom, so I had to take it out of the old filter - no problem but it is a large hex key - around 10mm but I didn't have one. Luckily a t55 bit that a fellow boater lent me was a good fit. I filled this filter with diesel and popped it on. Noticing a diaphragm thing on the top, I undid a bleed nut and gave the diaphragm thing a couple of presses until diesel squirted out of the bleed nut hole, then did up that nut.

That was it - the engine ran faultlessly from the off. I can't see any wires going to anything near the fuel filter so the jury is out as to whether there is an electric pump that sorts out all the air in the fuel... or if I was just lucky this time!

The fuel shut off valve was closed/opened at the appropriate junctures.

[Scholar Gypsy]

Very good. On my diesel engine course the instructor said that fuel filters would leak if they were overtightened or undertightened. 

In response to the obvious question the answer is "experience". 

The advantage of an electric fuel pump (which I have) is that you don't need to fill the filters with diesel before assembling them. I just run the pump for about 30 seconds and it fills the pre-filter and the engine filter, pushing air out through the top of the latter. 

I sometimes need to crack the banjo joint on the high pressure pump for a second or two, once the engine has started and is threatening to conk out, but it sounds you were lucky!

[Johny London]

No idea what a banjo thing is.

Anyway - upon inspection today, there seems to be a small weep from the hex nut bung plug under the engine filter (I wiped dry and will check again later). Will try nipping up the nut but my feeling is that I will need to undo it and replace whatever the seal is - pity the filters don't come with the necessary.

Not sure if the nut thing and seal can be purchased as an assembly, or if I just need another seal, or what any of it is called. I don't know the size/shape of the seal, so it's a bit of a pain really but at least I have a procedure now.

[Scholar Gypsy]

Drain plugs.

On one of my filters there is a hex bolt and a brass washer. If the latter gets distorted  (eg overtightening) then it needs to be replaced.

On the other there is a tap thingy that you hand tighten, and a rubber washer. Again this gets distorted if over-tightened.

I rarely use either, instead catching the fuel in an ice cream container or similar when I take the filter to bits to change it. I know that in theory one can drain a little bit from the bottom of the pre-filter, but one has to open the vent at the top to let some air in, and getting rid of that air (which is before the fuel pump) is a real pain. Last time I tried this route the engine conked out half a dozen times over the next couple of days, as a bit more air worked its way through the system. Never again! [I suppose I could refill the first filter through the vent hole].

Edited May 23, 2017 by Scholar Gypsy

[WotEver]

22 minutes ago, Scholar Gypsy said:

I know that in theory one can drain a little bit from the bottom of the pre-filter, but one has to open the vent at the top to let some air in...

Is your filter above the tank then? When I used to drain the pre-filter on WotEver it just ran out with the air behind the fuel in the tank. 

[Scholar Gypsy]

2 minutes ago, WotEver said:

Is your filter above the tank then? When I used to drain the pre-filter on WotEver it just ran out with the air behind the fuel in the tank. 

Yes it is.

My tank is very low, on either side of the engine bearers, with a connecting section that isolates the engine and stern gland bilges. The pre-filter is level with the uxter plate

[WotEver]

6 minutes ago, Scholar Gypsy said:

Yes it is.

My tank is very low, on either side of the engine bearers, with a connecting section that isolates the engine and stern gland bilges. The pre-filter is level with the uxter plate

Ahh, that's the difference. My fuel tank sat on the uxter. 

[mross]

2 hours ago, Johny London said:

No idea what a banjo thing is.

So-called because of the shape.  Often used on fuel pipe connections.

Edited May 23, 2017 by mross