How to clean fuel tank

[Sandy]

Bit of a long story here but please bear with.

Oh dear... that is a sorry sight.

I'd be all for slowly keel hauling the boat designer who put the tank in a place that it could not be removed!

If you want to save the tank it will need to be opened up - not easy as it has had petrol in it and with just a wee spark you might have an explosion on your hands - they make a real mess of the boat if you live to tell the tale.

I'd fill the tank with water, so not to risk being blown into the field 50 meters away, then find a man with cutting gear to make a big hole in the tank. It is accessible, if not add 50 lashes with a cat-o-nine-tails before the keel hauling? That gives you access to the joyous job of cleaning the tank or deciding that perhaps a new one would be a better idea.

Once clean you will need an inspection hatch fabricated.

 

[rogerthebodger]

I think is a keel hauling offence to not fit inspection hatches in all tanks. Fuel , Water and black water

My inbuilt steel fuel tanks have 2 inspection hatches in each fuel tank and one in each Stainless steel fresh water tanks and 2 in my GRP black water tank

 

[moresparks]

An off the wall suggestion.. but maybe worth a try - but time consuming.

How about dosing the tank with something like Startron Tank Cleaner, leaving for 24 hours then use a cheap hand transfer pump from the fuel filter output and “drawing” the fuel into containers. You probably need a couple of filters and pumps until clean.

Assuming the sludge is at the bottom the Startron should dissolve the sludge.

You may have to repeat the process a couple of times!!

 

[fisherman]

Get some outboard tanks to get away. Put some sort of solvent mix in the fixed tank and leave it for a season. Make sure to have a few sploshy days out. Then use an extraction pump to clean the fixed tank. You'll still worry, so fit a decent sediment tap, and keep the outboard tanks handy. ? ?

 

[Pete7]

then find a man with cutting gear to make a big hole in the tank. It is accessible, if not add 50 lashes with a cat-o-nine-tails before the keel hauling? That gives you access to the joyous job of cleaning the tank or deciding that perhaps a new one would be a better idea.

I have fitted an inspection hatch in a stainless steel petrol tank. The tank was glassed in a rib with the console glassed on top. After draining the contaminated fuel out and removing the filler and outlet pipes. I put a hose in it plus a good dose of laundry soap and left it running over night. Pumped the remaining water out then left it whilst I bought a box of 6mm drills. Vetus used to do fuel tank fittings and 6" inspection hatches. After marking out the tank I set to work drilling an awful lot of holes, then smoothed off the edges with an angle grinder. This gave me access to clean out the tank.

Worth noting, if the tank in question is 215L then it is likely to have baffles in it to stop the fuel surging back and forth but will make any cleaning task all the more difficult. I was able to reach behind the baffles in my tank.

 

[Lazysloth]

So what I think must have happened is that when the boat was on land and getting engine swapped out when I was running petrol through the tank and it was coming out clean the gunk was sitting on the bottom of this giving the illusion of a clean tank, then when we took her out to see to seatrail her it brought all the gunk to the surface and clogged the filter... This is my theory anyway.

I've been speaking to some of the guys at the marina and we have come up with a plan, similar to what moresparks has suggested . it's probably not the best and is time consuming but hopefully may work

I have a inline pump left off the old engine, connect this to the fuel outlet prefilter and pump the petrol out while ensuring the boat is rocking to bring up as much sludge as possible. Once empty leave the petrol canister to sit and then try sucking any more sludge left in the tank out via the small sender hole. Following this put the fuel bank into the tank minus and sluge which would have settled to the bottom and repeat the process with some tank cleaner in

 

[Refueler]

I wish you luck - but you are going to be at it for quite a while that way - if it works.

Problem as I see it - you are never going to be sure you have that residue fully out ... and sorry to be alarmist - it may just be one day yuou are out there, weather deteriorates and some decides to lift - engine stops.

Do you have a 'get you home' outboard on back end as many mobos carry ?

 

[Pete7]

I wish you luck - but you are going to be at it for quite a while that way - if it works.

Very likely.

However, since the petrol is no longer suitable for use as fuel, I would do a quick filter to remove the bits as you drain it off and put at least some of it back in again once the tank is empty. Ideally as quick as possible to loosen more gloop. Easier on a boat sat on a trailer as you can tip the boat and the tank so it runs to one end.

 

[AntarcticPilot]

You might be able to inspect the interior of the tank with an endoscope such as this: Amazon.co.uk

 

[Lazysloth]

I wish you luck - but you are going to be at it for quite a while that way - if it works.

Problem as I see it - you are never going to be sure you have that residue fully out ... and sorry to be alarmist - it may just be one day yuou are out there, weather deteriorates and some decides to lift - engine stops.

Do you have a 'get you home' outboard on back end as many mobos carry ?

No I don't have a auxiliary engine, i have been meaning to get one but all the money has been ploughed into this engine... I'm thinking in the mean time I may hook up a small extra plastic fuel tank with its own filter, should the worse happen at least I'll be able to fet home

 

[Lazysloth]

You might be able to inspect the interior of the tank with an endoscope such as this: Amazon.co.uk

I bought one of these but didn't really work out will, the fuel tank is to big for the lift to really show anything up, good idea though

 

[Lazysloth]

So this is what I'm working with. 5L container with fuel which has been sitting there for approx 1 hour

 

[AntarcticPilot]

I bought one of these but didn't really work out will, the fuel tank is to big for the lift to really show anything up, good idea though

I think that some less basic models are actually steerable, but it puts the price up.

 

[Lazysloth]

Hi guys
Okay I hate to say it but you were right I was wrong
I think I'm going to be at this forever. I was going to use plan B but just wanted to run it by some of you for safety really as never done anything like this before.
I was going to empty the petrol out of the tank, then fill it completely with water leaving the fuel line open to hopefully displace the vapours.
When the tank is full of water drill a couple of holes in the tank and allow the water to drain slightly. Then put the blade of a reciprocating saw in the holes made but the drill and ccut a panel out of the tank whole draining the water.

I believe a reciprocating saw will cut the metal while cold and avoid any sparks such as an angle grinder. When the tank is all clean get a large steel plate and weld it back over the hole (I know a guy who welds I won't be doing this) .

Any hints, tips or advice would be a great help as really not wanting to blow myself up. Thank you all

 

[burgundyben]

Have a look at the inspection hatch that Wema sell.

No need for welding.

FLB Tank Inspection Hatch

 

[rogerthebodger]

The plate you were considering welding back in would be better bolted on to the hole so it can be removed any time you wish to check the tank

If the plate is about 100 to 120 mm bigger you can drill holes around the edge about 25 mm in from the edges all round.

Start off with 6 mm. then place the plate on the tank and drill through the tank top.

Tap th oles jn the tank top M8 screwing setscrews from under side of the tank top

Open the holes in the plate to 10 mm dia then bolt thr plate onto the tank lid with some foam rubber strio to seal the lid

 

[Lazysloth]

Have a look at the inspection hatch that Wema sell.

No need for welding.

FLB Tank Inspection Hatch

Dude, thank you so much! This could be the answer to all my issues. Thank you only think is I don't have access to the top of the tank so will be putting it on the side. Thanks again

 

[Lazysloth]

The plate you were considering welding back in would be better bolted on to the hole so it can be removed any time you wish to check the tank

If the plate is about 100 to 120 mm bigger you can drill holes around the edge about 25 mm in from the edges all round.

Start off with 6 mm. then place the plate on the tank and drill through the tank top.

Tap th oles jn the tank top M8 screwing setscrews from under side of the tank top

Open the holes in the plate to 10 mm dia then bolt thr plate onto the tank lid with some foam rubber strio to seal the lid

See this sounds like a good idea but I'm not very good at DIY. I know myself I'll mess it up some how. The post above has mentioned a inspection hatch which seems easy enough to install. I think I'll give that a try. Thank you

 

[burgundyben]

Dude, thank you so much! This could be the answer to all my issues. Thank you only think is I don't have access to the top of the tank so will be putting it on the side. Thanks again

Whoa!

I dont think you can put it on the side.

 

[rogerthebodger]

Dude, thank you so much! This could be the answer to all my issues. Thank you only think is I don't have access to the top of the tank so will be putting it on the side. Thanks again

The issue with round inspection hatch is cutting a truly round hole in ant tank in situ/

A square or rectangular hole can be cut with an small angle grinder with a cutting disc the fit a rectangular lid with a generous overhang