Cleaning fuel tank

[Independence]

Having recently purchased a new boat (to me) I'm keen to ensure the fuel tank is as clean as possible.

There is no drain point other than the fuel pipe and I can't remove the tank.

So far I've drained all the fuel which looks reasonably clean. From the look of other maintenance on the boat (or lack of) I'd like to have a go at making sure there is as little muck in it as possible.

Are there any suggestions as to how best clean inside the tank without having to remove it?

Thanks

 

[Maurice55]

Is there no visiting trap at all, have you not got any way at all to have a look in there? If not I would sugest puting a little fuel back in and sucking it out with an engine oil sump pump kind of thing and then re filling with a good helping of anti crap gear,the best one having probably been discussed on this forum.

 

[Shearwater]

I posted an exact similar enq'y a few weeks ago and received a lot of hits, all well intentioned, about cutting holes in the fibrelass tank, etc etc. I was almost going to install a new and separate Plastimo tank until the guy in the boatyard suggested installing a 30 or 40 micron pre-filter with a glass bottomed water separator/checker and they would show me how to check for gobbets and replace filters. I thought this to be a highly cost effective solution and it is now being put into practice. Let me know your final decision - I'll be very interested to learn which way YOU go.

 

[Independence]

It's all a little cramped in there and having double checked by feeling around the underside of the stainless steel tank I'm sure there is no where to drain fuel other than the fuel pipe.

I've had 2 ideas of my own so far:

1) keep flushing clean fuel through (filtering it before I re-flush and blowing up the fuel pipe to disturb any bits of muck that will hopefully be drained out as the fuel is syphoned out. By luck the boat is currently stored on a slope with the bow and tank facing lower than is usual.

2) when the tank is empty try putting some sort of swab on the end of a piece of wire and mopping out any residue dirt. This is presuming there are no baffles in the way stopping me getting to the lowest point.

I have a glass bowl on my water seperator which will help me look for problems. I was trying to prevent them happening in the first place but the idea of additional filters is a good one and I may consider this if I feel I've not resolved an issues (assuming I have them in the first place as I haven't actually been afloat or run the engine for any period!!)

 

[vyv_cox]

As has been suggested, use a Pela oil vacuum pump. It will draw up any sludge and water that may be present, quickly and easily. Far more effective than a swab on a piece of wire, which may cause more problems than it solves. This would be my preferred option for mild contamination of a small tank.

Continual flushing of the fuel by the normal dip pipe will not help a lot, as it does not disturb any sludge that may be below the end of the pipe. To do this well you need to pump out the existing fuel using a hose pushed down the supply pipe to ensure that it reaches into the corners of the tank.