Under deck tank check

PeterM · 08 June 2009, 09:05

Hi All - I'm after some advice on how to check the pick up in my tank under deck. Last year I ' ran out' of petrol when I had used 120l of 180l in the tank. So my question really is what is the best way to check the pick up in the tank ?

Having never needed to look inside petrol tanks can anyone explain how the pick up works from an under deck tank?

The only access I have is under the rear seat - the filler pipe running vertically into the top , the breather vent , the tank sender unit & the feed to the filter/ primer.

Clearly the filler is a few inches diameter , the sender appears to be similar diameter & the feed & vent about 1/4 inch tubes.

Any advice or guidance welcome as I really want to be able to use all the petrol in the tank and not just 2/3 of it !

PeterM · 08 June 2009, 10:21

If I buy something like this :

http://cgi.ebay.co.uk/USB-RIDGID-SEE...3A1%7C294%3A50

& stick it in the tank ( when nearly empty ) does anyone think I will blow my self up ? Hopefully this will let me see the pick up pipe.

Is it likely the pick up is 'floating' ? - as I read in an old thread about a tank where the pick up floated when the tank was 1/3 full.

jambo · 08 June 2009, 10:23

Hi I had same trouble on my Ribcraft 2 years ago in that it kept telling me I hab 3/4 tank and the worst happened |I also ran dry in the middle of the Sound of Jura!1
It was the sender and not the guage (have you checked) once I had acertained the sender problem I actually phoned Ribcrafft who as usual were very helpful talked me thru thr process and me and a mate fitted the new sender and we have been ok since. Is there anyway you could contact maker as they will know the best and simplest way to tackle the problem. Hope you get it sorted soon.

J

PeterM · 08 June 2009, 10:44

Quote:

Originally Posted by jambo

Hi I had same trouble on my Ribcraft 2 years ago in that it kept telling me I hab 3/4 tank and the worst happened |I also ran dry in the middle of the Sound of Jura!1
It was the sender and not the guage (have you checked) once I had acertained the sender problem I actually phoned Ribcrafft who as usual were very helpful talked me thru thr process and me and a mate fitted the new sender and we have been ok since. Is there anyway you could contact maker as they will know the best and simplest way to tackle the problem. Hope you get it sorted soon.

J

Cheers - nice to know its not just me that has made one of th emost basic of errors..... I dont think its the sender as I ignore the guage and work on the fuel used info of the smart craft gauges. I know I used/ ran out after 120L as it took that much to fill up the tank after the engine stopped.

Have spoken to builder who confirmed its a 180 L tank , but I am sure that the hull & tank were both supplied by RING - then the tubes/ cabin etc were added. I'd like to understand & fix whatever has happened in there as I have never needed to look in a tank before & I'm quite looking forward to it ( in an odd way) .

bedajim · 08 June 2009, 11:40

Quote:

Originally Posted by Blackroady

Cheers - nice to know its not just me that has made one of th emost basic of errors..... I dont think its the sender as I ignore the guage and work on the fuel used info of the smart craft gauges. I know I used/ ran out after 120L as it took that much to fill up the tank after the engine stopped.

Have spoken to builder who confirmed its a 180 L tank , but I am sure that the hull & tank were both supplied by RING - then the tubes/ cabin etc were added. I'd like to understand & fix whatever has happened in there as I have never needed to look in a tank before & I'm quite looking forward to it ( in an odd way) .

Pull the engine feed pipe off at the tank and dip the tank with a rod to see how deep it is.

Bend the end of the rod over a couple of mm and do it again this time when you pull it up it should hook the end of the pipe, so you should be able to see the different lengths

When you reconnect the fuel hose cut the end off, as it's not good practice to refit the hose to the tail/pipe if you have some slack in the hose

Pete7 · 08 June 2009, 11:45

The other thing you could do is measure it with a tape measure then use google to calculate the volume which would confirm if it really is a 180L tank.

What's the tank made from? if it is stainless steel it should have baffles for that size which means looking inside is difficult. What you might see however is the pick up going to within 1/4" of the bottom of the tank. However what the fabricator did on the day he made it...........

Nothing lost having a good look, would also show any water / dirt etc inside.

Pete

Nasher · 08 June 2009, 11:53

Never trust the fuel gauge on a RIB.

can I suggest you invest in a flow meter, as you won't look back.
once calibrated you'll know exactly how much fuel you've used at all times, along with other information.

The one I have is a Navman, that uses a sender in the fuel line and a gauge in the dash thats completely seperate to all other systems.
Also known as a Fuel Computer, I think it was @£80 in a sale.

Nasher.

PeterM · 08 June 2009, 12:00

Cheers - good idea on cutting a bit off the pipe. Its a SS tank under deck so not sure how I can measure it & then work out the volume ( apart from some liberal guesswork).

I do think the pick up will have lifted as with 1/4 inch off the botom I xpcet to have 5- 10 litres of unusable petrol , but with 60 l I think its mre like 10 inches off ! Nothing else will explain the engine cut at 120 l used ( unless its a 120 l tank! Which I am assured its not)

The smartcraft gauages do have a fuel used display so I alway use this down to about 80-90l used & at that point fill up - so am sure( as I can be I wont run out again ! )

If I pull the sender unit out will that give me a 2.5 inch hole to look in ?

Nasher · 08 June 2009, 12:09

Quote:

Originally Posted by Blackroady

If I pull the sender unit out will that give me a 2.5 inch hole to look in ?

It should do.

I must admit that when I needed to look in mine, I used an LED waterproof torch borrowed from one of my lads, as I figured the rubber waterproof body would prevent any chance of a problem, but even so I turned it on and off well away from the open hole.

Nasher.

codprawn · 08 June 2009, 12:49

You could always purge the tank with CO2 - ie pub gas.

Empty the tank into jerry cans using a syphon and you could sucjk out the last dregs using a vacuum oil sucker.

Observer · 09 June 2009, 14:43

Quote:

Originally Posted by Pete7

The other thing you could do is measure it with a tape measure then use google to calculate the volume which would confirm if it really is a 180L tank.

What's the tank made from? if it is stainless steel it should have baffles for that size which means looking inside is difficult. What you might see however is the pick up going to within 1/4" of the bottom of the tank. However what the fabricator did on the day he made it...........

Nothing lost having a good look, would also show any water / dirt etc inside.

Pete

Google?!!

L x W x H (in cm) = volume. Divide by 1000 for capacity in litres (ignoring material thickness). Divide again by 4.54 for imperial gallons.