Fuel filter change

[mick]

I remember reading somewhere that a fuel filter change should be made once the boat has been used for a while at the start of the season, the reasoning being that the old filter would catch any crud disturbed by the motion of the boat after lying around for the winter. I have always followed that advice as it seems reasonable, but this season it would suit me to change both primary and fine fuel filters while the boat is sill in the yard. Thoughts? Might it be an idea to change the primary filter now and the fine filter after launch?
Edit:that should of course be fine filter now and primary after launch.

 

[prv]

The idea makes a certain amount of sense, but personally I wouldn't organise my life around it.

Pete

 

[earlybird]

I change my fuel filters after launch. That way it's easier to test run the engine for a time.

 

[lpdsn]

... but this season it would suit me to change both primary and fine fuel filters while the boat is sill in the yard. Thoughts?

Like Earlybird I always change filters when the boat is in the water. It means I can run the engine for a while to check everything is OK before unmooring. Worst time for the engine to fail is when leaving the lifting dock after being put back in, especially if windy.

I also fitted a vacuum gauge between primary filter and lift pump over the winter. Cost me €7 from China. Other bits and pieces probably trippled that figure, but still worth it. Gives me the means to monitor the filter.

You could try seeing how hard the lift pump is to operate manually, which should give you an idea of whether the filter is getting blocked. I also found out you can suck up to 7lb/sq in whilst experimenting with the gauge before fitting it. So if you can't suck diesel through the pipe that would be another indication of a blocked filter.

 

[mick]

Thanks for replies.

 

[prv]

I also fitted a vacuum gauge between primary filter and lift pump over the winter. Cost me €7 from China.

I have the same. Originally fitted to help monitor the filters during a bug infestation, but I would now recommend it on any boat.

Pete

 

[lpdsn]

but I would now recommend it on any boat.

Definitely.

I my case I suspect the problem was bio-diesel-gloop in the copper pipes caused by using white diesel too much (buying it south of the border is competitive with red at 60:40).

It seems to be sorted now through judicious use of snake oil, but it was interesting to see the vacuum going up as the gloop was forced through the pipes then suddenly dropping as it reached the filter. I would've known nothing about it from the note of the engine.

I even considered writing up the fitting of the gauge for PBO, but decided they probably wouldn't be interested and didn't bother taking any photos in the end.

 

[jonrarit]

I even considered writing up the fitting of the gauge for PBO,

If you fancied writing one up for us, I'd be interested in reading it? What parts you sourced and how it as plumbed in. Sound like one of the simple but effective ways of monitoring the otherwise "ignored-until-it-goes-wrong" parts of the boat

thanks in advance

jr

 

[prv]

If you fancied writing one up for us, I'd be interested in reading it? What parts you sourced and how it as plumbed in.

It's not exactly complicated - get a vacuum gauge from eBay and tee it into the fuel pipe between the lift pump and the first filter. My gauge reads from zero to -1 bar; when the filter completely blocked and the engine stopped it only went halfway round the clock so maybe a -0.5 bar gauge (if such a thing exists) would give a more accurate reading in normal use. But mine is fine. Here's an example, but there are loads of them: http://www.ebay.co.uk/itm/Vacuum-Ga...-8-BSPT-BACK-Optional-Hose-Tails/321687215074 (price is actually £6.95, the £1.95 is for a hose tail and is a common trick for pushing up their ebay listing).

I ran the hose to the gauge upwards from the tee to prevent it filling with diesel, but quite possibly this doesn't matter.

Pete

 

[colind3782]

If you fancied writing one up for us, I'd be interested in reading it? What parts you sourced and how it as plumbed in. Sound like one of the simple but effective ways of monitoring the otherwise "ignored-until-it-goes-wrong" parts of the boat

thanks in advance

jr

+1

 

[lpdsn]

If you fancied writing one up for us, I'd be interested in reading it? What parts you sourced and how it as plumbed in. Sound like one of the simple but effective ways of monitoring the otherwise "ignored-until-it-goes-wrong" parts of the boat

thanks in advance

jr

OK, here goes. No pictures I'm afraid. As prv says, it's pretty simple.

I bought the vacuum gauge from Banggood (cost €7.38 at the time). http://www.banggood.com/2-p-906588.html
It usually takes about three weeks for them to deliver - longer if customs sit on it for a while as Irish customs seem to have taken to doing recently. The vacuum gauge has a 4mm connector on the rear.

I bought 1m of 3.2mm fuel hose on Amazon, gambling that it would fit the 4mm connector which it did. Cost £3.69

I also bought an 8mm/4mm nylon T-piece via Amazon (actually from Advanced Fluid Solutions). Cost £5.04 including delivery.

I cut a 2" hole in the plywood surrounding the engine. I didn't cut into the sound proofing, which meant I could use a screwdriver to gentle poke a hole just big enough for the hose. If you have lead in your soundproofing, you may need to drill it.

The 2" hole wasn't quite big enough - clearly the inch isn't that standardised in China, which was also the source for the 2" hole cutter. So I needed to do a little bit of filing to get the gauge to fit.

I chose to fit the gauge low down because I felt better about that from a fire point of view. It's about an inch above the cabin sole so I have to bend down to look at it, but my theory is that if there's an engine fire it won't get very hot down there in the short term.

The 8mm hose between the primary filter and lift pump was joined already at just about the right place. I used about 1.5" of 8mm rubber diesel hose to join the original join with the T-piece, which in turn was joined to the other part of the original hose. How easy it will be to find a place to fit the T-piece will depend upon how your current hose is fitted.

That was basically it.

There is a light in the gauge which I wired up via a small switch that I fitted nearby. It was fused through existing wiring I'd put in for a voltmeter. Of late I've taken to fitting round switches rather than rectagular ones as it can be done in a few minutes with the right sized hole cutter. Switch came from China too. http://www.banggood.com/5Pcs-Mini-Round-Black-2-Pin-SPST-ON-OFF-Rocker-Switch-Button-p-946012.html

 

[lpdsn]

Other information:

I posted on here to ask about reasonable expectations of the vacuum reading and pvb's posts were helpful.

http://www.ybw.com/forums/showthread.php?420934-Vacuum-at-Primary-Filter

The vacuum started off at 5lb/sq in (new filter after I lost the engine the last time out before fitting the gauge).

Testing whilst tied up at the pontoon over about 90 mins: the vacuum slowly increased to 10lb/sq in, before dropping very quickly back to 5. Consistent, in my mind, with gunk being sucked through the pipes.

Went for a sail early Feb (actually a motor in nice sunny weather). Increased slowly to 8lb/sq in before falling to about 4. Fine the next day motoring back. Did nearly 60 miles under engine a few weeks ago with no issue and no peak in the vacuum. Seems to sit quite happily between 4 & 5 lb/sq in at about 2,200 to 2,400 revs. This is still the same primary filter that has the gunk that came out of the pipes in it.

As I posted earlier in the thread, it's great being able to see what is happening, rather than having it in the back of my mind that the filter may be blocking up and just waiting for the first stuttering of the engine.

I also bought some fireproof tape from Amazon (sticky-back cooking foil really) to wrap around the T-piece, but I've not fitted it yet.