Lister Engine Forum

How to / DIY => Engines => Topic started by: Undergrowth on June 04, 2021, 12:23:17 PM

Title: Fuel leak ST1
Post by: Undergrowth on June 04, 2021, 12:23:17 PM
Hello all,  I am hoping to make use of your knowledge and experience as I don't have much of either when it comes to Lister generators.

I live in an off-grid house and we occasionally use our 1983 Lister ST1 to run the washing machine, or for power when the weather isn't co-operating with our hydro and solar systems.  The Lister has sprung a slow fuel leak - it is leaking from the bottom of the fuel tank, where the fuel pipe screws in to the tank.  I haven't yet dismantled it all and had a good look, but am wondering 1) the best way of emptying the fuel tank 2) if this is a common problem, and 3) if it's easily solvable or whether we are likely to need a new tank.

I have tried tightening up the nut but that hasn't helped.  It's all so ancient I am worried about making things worse.

Any tips welcome!


Title: Re: Fuel leak ST1
Post by: cobbadog on June 04, 2021, 12:55:57 PM
Gday Jacinta and welcome to the forum.
Not sure iff you can see the fuel line connection cleaarly while it is in place but if you canwipe it as dry as possible and with a good light see if you can pin point where the leak is comming from. Some ideas are;
Hole in fuel tank.
Fracture of the solder/brazing of the connection where it is attached to the tank.
Your fuel line may need to be replaced due to a flare or olive failure which is how most fuel lines seal. (I am going through this now on one of the tractors).

To fix this leak will depend on where it is comming from. If it is a hole than a patch might be able to be soldered or brazed on same for a leak around the outlet. Here in Australia there are fuel tank repair kits available and these are a simple 3 step proceedure but pricey. A kit to do a large fuel tank say from a car is around AU$150.00. If it is the fuel line and you have no way of making another one take it to your local hydraulics shop and they will make you a new one that will bolt straight on.

I have an SR2 engine with the fuel tank that holds around about 1 gallon so it can easily be unbolted, lifted ot and emptied into a fuel tin using a funnel. If you have a larger tank then either a syphon to get as much out as possible or disconnect the fuel line somewhere so that you can then push a flexible plastic hose onto it and let it drain into a fuel can.

It is not a common problem but if it has gone rusty inside maybe finding a replacement tank is best and you should be able to adapt any kind of tank to do the job so long as you can mount it above the injector pump to be a gravity feed it will work. I used an old plastic lawn mower tank for a few years on our old 8hp CD Lister until I found an original tank that held about 2 gallons.

Good luck with finding the problem and keep us informed as to what you found and what you can do to fix it. Others may chime in with better ideas and help.
Title: Re: Fuel leak ST1
Post by: Undergrowth on June 04, 2021, 01:01:29 PM
That's really helpful - thanks so much!  I will start doing some investigating and see where I get to. (I'm in the UK, by the way)
Title: Re: Fuel leak ST1
Post by: cobbadog on June 05, 2021, 06:50:24 AM
Yes, and I'm just around the corner in Australia but I will still talk to you.  :laugh:
Title: Re: Fuel leak ST1
Post by: Undergrowth on June 05, 2021, 02:15:25 PM
So, I've taken the tank off and it seems the problem is a fracture of the solder/brazing of the connection (nut) where it is attached to the tank.     There are also a couple of pinholes under one of the brackets, which much have been gunked up and only became evident once I started removing the tank.  A tank repair kit seems like a good idea - do you think this would repair the fracture? There is some movement in the nut.   

The olive on the pipe looks ok - but there is something that looks like PTFE plumbing tape wrapped around the pipe under it.  If I were to replace this, would PTFE tape do the trick? (hopefully that's a universal name, not just UK).

Title: Re: Fuel leak ST1
Post by: cobbadog on June 06, 2021, 12:38:06 AM
Glad you found a problem. The fracture can be brazed again and at a reasonable cost because of how quick it can be done. As for the pin holes depending on how bad they are as to which way to go. These too can have a large patch soldered or brazed over the area but to make that decision you will need to remove the paint with a light grind to be able to access the damage.
A tank repair kit might be able to do the job but again you will need to see how good or bad it is by removing the paint and I would clean the complete bottom area of the tank first because if it has pin holes in one place there is bound to be more.
Hard to offer best advise without pics but in the mean time I would search for a replacement tank which could work out cheaper than a repair. There are Dumpy parts suppliers in the UK and I think mainly Winget parts but a fuel tank is interchangeable with them or should be.
Have a good look inside the tank through the filler cap and see how it looks inside.
Some very basic methods of cleaning up inside tanks can be the use of blue gravel and shake it up for a long time to loosen the rust.
Electrolysis works very well for cleaning metal parts up. Mix water and soda ash. Place the tank in a large tub so that it is submerged then an anode hanging inside the tank and the other lead to the tank. The anode must be insulated and not touch the tank itself just hang freely inside then connect a battery charger to it.
The use of Hydrochloric acid works too but needs to be neutralized extremely well by the use of a lot of clean water.