Twin fuel tank install
Submitted by Ashen on Tue, 2017-01-17 22:34
Hi guys.
Putting in twin fuel tanks and wondering what's the best way to plumb them? I was thinking of plumbing the tanks into a 4 way valve (1, 2, both, off) and from there, into the fuel filter/water seperator. Another thing is, my fuel filter has twin in and out. Can I plumb directly from the tanks into the filter, and not worry about the 4 way valve, and have individual shut off valves for each fuel line/tank?
Ideally I would like the motor to pull fuel from both tanks at the same time to keep fuel levels even.
Suggestions?
Ranmarrrrrr, where are you?? Haha
Thanks!
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Tim
Posts: 2497
Date Joined: 26/09/06
Filter
Feral
Posts: 1508
Date Joined: 01/11/06
it's not recommended to pull
it's not recommended to pull fuel from both tanks at the same time. If one empties faster for any reason them it will suck air into the carby and starve the motor when it runs out. depending on what you are doing with the boat I'd plumb both lines into a T valve then head to filter. if you plan on heading extended trips then you have a spare inlet on the filter to connect a quick release out board fitting and clip on 20Lt tanks for added range (or a fuel bladder etc)
Comrad
Posts: 109
Date Joined: 17/07/14
I like the idea of the quick
I like the idea of the quick release fitting there for quick addition of extra tanks. I was looking into adding a second tank myself. I had sort of liked the idea of having the tanks manually separated, and with the secondary tank being as big as the primary, or greater, so when you're out super wide, and you can run out of fuel in the primary, and then know that you've got the same amount of fuel to be able to get back home, I'm always paranoid about running out of fuel, since I only have a calculated fuel guage, rather than a level sensor.
Each to their own, though.
Feral
Posts: 1508
Date Joined: 01/11/06
it sure makes life easier to
it sure makes life easier to add fuel containers with no pouring etc.
I have a 200l fuel bladder for long runs that I use for the trip out that once empty gets folded away. and if more is needed then outboard fuel tanks can be used
Comrad
Posts: 109
Date Joined: 17/07/14
I don't want to hijack
I don't want to hijack Ashen's thread, but, I'm curious about the fuel bladder idea, I like the idea of using it to head out, then folding it away. I imagine being a bladder it sort of flops all over the place when you're using it? Does it just sit on the deck, or do you have a frame for it? Also, where to you get them/price, etc... and are the dimensions standard, or do you have to get them custom made?
Feral
Posts: 1508
Date Joined: 01/11/06
they can slosh around a
they can slosh around a little but mine goes up the front in the foot well between the bunks. It can go out on deck tho with no issues, the one I have is square and it deflates as the fuel is used. It packs away to a size of 30x60x20 cm so it's not wasting space. I think mine is branded fleximake (but I might be wrong on that) I picked it up for $150 second hand... I'd prefer solid tanks eg. 3 x 75l or 2x 90l but the cost for those is horrible
Rob H
Posts: 5797
Date Joined: 18/01/12
Depends where your tanks are
Depends where your tanks are located.
If its a cat or your tanks are athwartships then you'd want them running simultaneously.
If they are fore and aft, Im not sure why youd want them both on under normal circumstances?
Kind of like dual batteries and running them on both.
As Tim says though plumb both straight to filter BUT, best to prime both up to there as a habit so if you need to switch tanks in a hurry there is no hesitation.
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Ashen
Posts: 1042
Date Joined: 22/03/13
Thanks
Great advice.
I should've been more specific. Tanks will be fore and aft, one under the motor well and the other will be located at the front. Total capacity of 180 litres. That should give me some good range!
Will plumb directly to filter with individual valves.
Thanks guys!
A fish in the hand is worth 10 in the water!
scano
Posts: 1247
Date Joined: 31/05/07
Couldn't you
just plumb one tank directly into the other. So basically linking the 2 of them at the base of one another via an adjoining fuel hose. Then just have a fitting coming off one that will connect the main fuel line and then you are done.
Ashen
Posts: 1042
Date Joined: 22/03/13
Yeah
Yeah mate, have thought about it. But I want a bit of redundancy. If one fuel line leaks (fken hope not! Haha), then I can switch it off using the valve and just run the other tank.
But if using only 1 main fuel line and it leaks, then both tanks are pretty much unusable..
Apparently, linking fuel tanks at the base is a big no no!
A fish in the hand is worth 10 in the water!
ranmar850
Posts: 2702
Date Joined: 12/08/12
Not a good idea to have no shut off between them
For a start, a leak in the joining hose will see you with no way of not emptying both, unless there is a valve on the outlet of each tank. On the plane fuel will be running from the front into the back, ( if they are mounted along the centreline)when you drop off the plane it will likely be running back again. You will really be scratching your head trying to work out just how much fuel you have left even with gauges on both. Unless you subscribe to the philosophy of always having full tanks, every single trip, and only using a bit, it doesn't really work very well,although the idea of simplicity has merit in itself.
I'dgo with the suggestion of having easily accessed taps close to the dual inlets on the filter as the best, most useable allround solution. There may even be a benefit down the track of diagnosing problems with fuel contamination, easy to see which tank it is coming from just by changing taps and looking at the sight glass.
sea-kem
Posts: 14978
Date Joined: 30/11/09
Another point to be
Another point to be considered Kev is with front and rear tanks you'll have a trim issue if the tanks are big enough. So having them separate and draining the rear tank first and having the front tank with reserve fuel to help you get the nose down. Like Ranmar said having separate helps with diagnosis of fuel issues too. Have you got the tanks yet?
Love the West!
Ashen
Posts: 1042
Date Joined: 22/03/13
Picking the tanks up next
Picking the tanks up next week, mate. 2x 90L Moeller tanks.
Yeah, I'm aware of potential trim issues with front and rear tanks. I will be repowering the 120hp to a 150-175hp around mid year. The larger outboard will weigh more. Having said that, I am planning to move the 2 batteries forward to save a bit of weight at the stern.
A fish in the hand is worth 10 in the water!
sea-kem
Posts: 14978
Date Joined: 30/11/09
It all helps, my boys who
It all helps, my boys who are no longer boys have to sit forward now on mine as it makes a huge difference. Especially when it's swelly.
Love the West!
Ashen
Posts: 1042
Date Joined: 22/03/13
Yeah, adding to the list is
Yeah, adding to the list is an anchor winch with chain and 100m of rope and the weight all adds up!
Ok, thats enough info until "The beast is unleashed". Haha
A fish in the hand is worth 10 in the water!