I'm trying to trace a slow leak that has created a large puddle of diesel fuel in my bilge over a period of 4 to 6 weeks. In tracing the fuel lines from the tank to the engine, I found a problem with one of the fuel hoses that might be the source of the leak. I'll fix this first, then see if the puddle reappears.
The tank is mounted at high level in the port cockpit locker. At the outlet, it has a turn-screw tap (to turn off the flow into the fuel lines) with an 11mm outlet nipple (measured at the thick end with calipers). This connects to a fuel hose, which connects to a fuel/water separator and is shown in the photo below. The fuel/water separator has a 7.9mm or 5/16" inlet nipple. The hose is marked 7.9mm 5/16" SEA 30R7, and fits nicely onto the fuel/water separator inlet nipple. However, when I tried to fit it onto the larger tank outlet nipple, I split the outer casing of the hose.
What I think has happened is that a previous owner had used the single piece of hose to connect the tank to the fuel/water separator. It worked previously, but it has now begun to split at the tank, leading to the slow leak.
I'm thinking of making up a new connection between the tank and fuel/water separator with two hoses joined end to end. The larger 11m hose will fit onto the tank outlet nipple and the smaller 7.9mm will fit onto the fuel/water separator inlet nipple.
Is there a joining piece or taper that will join the two hoses end to end? Can you get tapered fuel hoses?
It would be easiest to install a larger or smaller hose barb at the cock or the filter I'd recon
Select to expand quotewoko said..
It would be easiest to install a larger or smaller hose barb at the cock or the filter I'd recon
Yep, or a reducing bush at the tank and then a hose barb of the same size as the filter.
Be careful with the filter barb.
CAV for instance has a special fitting which should be used.
Not entirely sure I understand the question but you can buy reducing barbs. Look on eBay for a brass reducer barb. Here is a link to an example.
I am about to use one as the diesel return on the Yanmar is 6mm and an 8mm hose has been used. It doesn't seem to leak but it slides off too easily for my liking even with a hose clamp on it.
www.ebay.com.au/itm/8mm-to-6mm-Hose-ID-Brass-Reducer-Barb-Fitting-Straight-Connector-Coupler-2pcs-/303326386080?_trksid=p2349624.m46890.l49292
I did not know it was called a Barb.
So, I can get a 10mm to 8mm barb or splicer in brass. However, brass is not the same as bronze and it corrodes too easily on boats. So I have started to look for stainless steel or bronze. Bronze does not seem to be available in the smaller pipe sizes.
Interestingly, some home brew outlets sell 304 Stainless splicers, which could do the job. E.g. www.triplejhomebrew.com.au/stainless-splicer-6mm-x-8mm-7544.html for $1.71
I'd probably also fit a couple of stainless steel hose clamps to stop it sliding off too easily.
Finally, what does "CAV" mean in the ads?
I think hose tail is the term for the barb bit, a reducing bush will screw in where the tail/ barb was and the new tail /barb screws into the bush. One size hose, no extra bits to contend with, stainless is good.
Select to expand quoteAchernar said..
I did not know it was called a Barb.
So, I can get a 10mm to 8mm barb or splicer in brass. However, brass is not the same as bronze and it corrodes too easily on boats. So I have started to look for stainless steel or bronze. Bronze does not seem to be available in the smaller pipe sizes.
Interestingly, some home brew outlets sell 304 Stainless splicers, which could do the job. E.g. www.triplejhomebrew.com.au/stainless-splicer-6mm-x-8mm-7544.html for $1.71
I'd probably also fit a couple of stainless steel hose clamps to stop it sliding off too easily.
Finally, what does "CAV" mean in the ads?
Brass in this situation with diesel running through it should last 50 years or so. CAV is the brand name for fuel/water separator that will guarantee an air leak on a regular basis.
Select to expand quotegarymalmgren said..
CAV fuel filter.
NOT recommended
Interesting.
So if you own a stack of CAV filter cartridges, is there any other housing type/brand that they can be used in, that are not prone to these air leaks? Or is the only option to bin them?
A bit harsh on the cav type filters, I've had em on many machines & ive used many brands of cartridges. A bit fiddley yes but if you replace All
the rubbers supplied they're ok, not as simple an install as a screw on job admittedly
Select to expand quotewoko said..
A bit harsh on the cav type filters, I've had em on many machines & ive used many brands of cartridges. A bit fiddley yes but if you replace All
the rubbers supplied they're ok, not as simple an install as a screw on job admittedly
I too don't have a problem with them, I have installed hundreds of them on all different types of equipment and as long as your careful they will fit together and seal up . I use one on my boat
I used CAV filters for more than 20 years on my fishing vessel. They are cheap. They are tricky to get the seals right. Not much of a problem if you have good access, I used to sit on the engine mount with the filter housing right in front of me and most of the time I would have a correct install. If you have to lay on your side and work with your arms out stretched then it might pay to invest in a Ryco Chinese made water separator with a superb quality alloy casting and a glass bowl with the sides that fully contain the O ring. I'm going to chuck the CAV housing in Ricochets engine room and fit a Ryco unit the other side of the bulkhead in the heads. Tons of room there and very easy access.
All of those observations seem right to me.
Reliable, cheap but you have to be careful to get the seals right.
Hi Wko
Re A bit harsh on the cav type filters, I've had em on many machines & ive used many brands of cartridges. A bit fiddley yes but if you replace All
the rubbers supplied they're ok, not as simple an install as a screw on job admittedly
I wasn't reviewing CAV filters , Just saying, not recommended.
As in.
"Hey, Gary I am going to fit a new fuel filter. Wodaya reckon?*
Me. "Well. I wouldn't go for CAV, They may be cheap, but they are too fiddly and after all these years they haven't gotten around to sorting out a better filter sealing system. Seems a bit lazy to me."
"So?"
"Well, I am sure most would disagree but, If you want a good reliable fuel filter.
Go down to a truck wrecker's and get yourself one from a (small) Japanese diesel truck or van.
They will mostly be Denso. Filters readily available too. On the other hand as Ramona said," It might pay to invest in a Ryco Chinese made water separator with a superb quality alloy casting and a glass bowl with the sides that fully contain the O ring."
Either way avoid the CAV would be my recommendation."
However if you have one fitted and it works for you, stick with it.
I totally agree Gary if I was starting from scratch I would go for spin on job, with a built in priming pump. For comparison sake I'm just now servicing my bt 50 Mazda the lovely spin on fuel filter is $24
Select to expand quotewoko said..
...I would go for spin on job, with a built in priming pump. For comparison sake I'm just now servicing my bt 50 Mazda the lovely spin on fuel filter is $24Select to expand quotegarymalmgren said..
Go down to a truck wrecker's and get yourself one from a (small) Japanese diesel truck or van.
They will mostly be Denso. Filters readily available too.
May I ask, gentlemen, whether these beautiful "spin-on" jobs used in the Jap trucks and cars, have transparent housings or drain cocks or other means to check if and how much water has been trapped?
The one I just changed has a float mechanism that sends a signal to command central then to a light on the dashboard. All very nice but if I installed one on a boat I would just put a water trap in the line pre filter
Select to expand quotewoko said..
The one I just changed has a float mechanism that sends a signal to command central then to a light on the dashboard. All very nice but if I installed one on a boat I would just put a water trap in the line pre filter
Exactly!! The best mod I made to the fuel system was a sedimenter/water separator for each tank prior to the primary filter.
Apologies to the OP, but I'd like to extract useful info from these gents while the subject is hot.Select to expand quoteUncleBob said..
..The best mod I made to the fuel system was a sedimenter/water separator for each tank prior to the primary filter.
Nice idea; any chance of pointing to a product(s) readily available in Australia, that is a dedicated water trap?
Nice idea; any chance of pointing to a product(s) readily available in Australia, that is a dedicated water trap?
Sorry if you didn't catch it Karsten
"Well, I am sure most would disagree but, If you want a good reliable fuel filter.
Go down to a truck wrecker's and get yourself one from a (small) Japanese diesel truck or van.
Isuzu. Mitsubishi. Nissan, Toyata. Hino.
Select to expand quoteKarsten said..
Apologies to the OP, but I'd like to extract useful info from these gents while the subject is hot.UncleBob said..
..The best mod I made to the fuel system was a sedimenter/water separator for each tank prior to the primary filter.
Nice idea; any chance of pointing to a product(s) readily available in Australia, that is a dedicated water trap?
Hi, I got mine from western filters in Sydney.
5836B120 Delphi CAV Watertrap Filter Sedimenter Unit.
Here is the repair. You can see the stainless steel tank, with a screw-down isolation valve/tap. Then, there is is a short section of 9.6mm hose with a hose clamp at either end. Then the stainless steel pipe reducer (only the central portion is visible). Then 7.9 mm hose with a hose clamp at either end, which joins to the Ryco water separator. The parts were less than $20. The engine runs, so fuel is getting through (made sure I bled out the air before trying to start it, this time). I'll have to wait a few days to see if it has fixed my slow leak.
Select to expand quoteAchernar said..
Here is the repair. You can see the stainless steel tank, with a screw-down isolation valve/tap. Then, there is is a short section of 9.6mm hose with a hose clamp at either end. Then the stainless steel pipe reducer (only the central portion is visible). Then 7.9 mm hose with a hose clamp at either end, which joins to the Ryco water separator. The parts were less than $20. The engine runs, so fuel is getting through (made sure I bled out the air before trying to start it, this time). I'll have to wait a few days to see if it has fixed my slow leak.
that tight bend were the hose rubs on the ply is going to give you trouble and possibly pinch and close ofalso not good to be rubbing on the ply ,better to change the fitting on the tap to a elbow
Select to expand quotegrich62 said..
that tight bend were the hose rubs on the ply is going to give you trouble and possibly pinch and close of also not good to be rubbing on the ply ,better to change the fitting on the tap to a elbow
Yep, you don't want it touching!! Even if you shorten the hose a bit which will stop the rubbibg & also get rid of the kink in the hose.
Best option, though, would be to get a fitting that will screw into the filter that has a 10mm/3/8" barb - then probably go with a 3/8" elbow as well. Have you got a "bolt shop" near you where you can take the barb fitting in to get the correct thread size??
Or www.ebay.com.au/itm/Brass-Hose-Tails-Plumbing-Fittings-Barbed-Male-Thread-BSP-9-Sizes-Available/113676622752?hash=item1a77a79ba0:g:d9gAAOSwJ~RZuKKt
Going to start a war here now
you have the fuel hose connected to the wrong end
better connected to the outlet for marine use
getting my coat!
Going to start a war here now
you have the fuel hose connected to the wrong end
better connected to the outlet for marine use
getting my coat!
Select to expand quotewoko said..
Now that's an interesting observation. I can't wait for the theory behind it
It is a good theory, but some would say law of diesels.
Look carefully at the filter.
