Hello

[nickmick]

Hello. I'm helping a buddy get a 1966 Monza 250 running. We got spark without too much trouble. Now we just gotta de-rust the fuel system.

Any tips appreciated!

[Bob_Matthews]

Use a remote/portable/hanging fuel tank whilst you sort the rust issue out. Rust particles in the carb wont help, so make sure it's perfectly clean.

[themoudie]

Aye Nick, a small electric concrete mixer and plenty of old towels/sheets makes the agitation of the small bits of metal and lavatory pull/bath plug chain inside the tank a lot easier on the arms. Just need to ensure that the tap holes and the filler cap hole are well sealed and change the position of the tank, so that the whole of the inside gets abraded.

White vinegar, apple vinegar are also good at dealing with the rust. There are lots of videos on YouTube etc. View more than one and work out your own technique. Personally, agitation and some small but coarse edged bits of metal along with the vinegar, help ensure the rust comes away from the inside of the tank. Rinse with plenty of clear water and finish off with boiling water and a touch of washing up liquid, followed by more clear water. Then use a hot air gun or inside your greenhouse or polytunnel to dry the tank out. You can then either treat the inside (or patch up the holes!) with whatever product resistant to ethanol you prefer. Again, take your time and ignore the bluster.

If I can get away with it, I prefer a litre (2 pints) of fuel, plus a measure of Briggs and Stratton 'Fuel Fit', with a 50:1 measure of quality 2stroke engine oil (chainsaw) Oregon/Partner, all mixed together and then sloshed around the whole of the tank. The 'Fuel Fit' stabilises the fuel and the 2stroke leaves a film inside the tank.

Happy sloshing and use the small remote tank for all your tuning etc. So much easier than having to take the tank on and off all the time.

Good health, Bill

[nickmick]

Thanks for the tips guys. Ripped the carb apart, soaking now. Whole thing is in surprisingly good shape. My buddy decided to buy new points for it. And now we can't get spark anymore. Two steps forward, four steps back. We'll get 'er.

Bill, what part of Scotland are you from? I was there two years ago almost to the day. Couple days in Edinburgh and a couple days near Loch Leven (Kinross). Beautiful country. Can't wait to go back.

I'm near Milwaukee, Wisconsin.

[cooperplace]

When removing rust from the inside of a tank, I use a length of chain. It's so much easier to get it out.

[themoudie]

Aye nickmick,

Just a wee bit further north to the west of Perth. Pleased you enjoyed your stay, but the dreaded lurgy is doing the rounds, so give it a bit of time.

Good health, Bill

[Dodge]

I have a rusty Mark 3 tank that I have derusting internally. Step 1 was the mechanical method already recommended by others. I used some largish steel nuts threaded on string. Step 2 was using the electrolysis method. I definitely recommend it – very clean and easy. The information on this forum and others has been very useful. However, there is critical detail missing. What concentration of washing soda (Sodium Carbonate – NA3 CO2) to use? How much current? (one Utube video uses a electric welder set to ‘low’ amps!)

My set up uses a 12VDC 2amp power supply (ex Scaletrix). I mixed 250g of Washing Soda in 12 litres of water, poured into tank. Anode (-ve black wire in picture) is connected to bare metal on the tank. (4 wires interconnecting bolts through petcock holes and tank mounts underneath + black wire to exposed metal at tank filler hole). Cathode (+ve red wire) to insulated mild steel bolt through filler hole. Ammeter connected to cathode and anode shows +00.12 mA when current is switched on.

I left the set-up running overnight. In the morning the cathode was suitably bubbly and covered in a brown/black gunge. Drained off the brown soup and cleaned the cathode; rinsed and drained tank with clean water. Second run repeating the procedure. Less deposits on anode and brown soup not so thick. Third and final run produced more gunge. However, steel interior of the tank is not the shiny steel that other people seem to have achieved. The rust appears to have largely gone but the steel is a dirty grey with a lot black spots. I think that an increase in soda concentraction and current (amps) might improve the speed of the process. (professional chemists can no doubt provide the best proportion and current). I then washed out the tank with clean water followed by a washout with 2 litres of 50:1 petroil 2-stroke mix (that I later used in the 2-stroke chainsaw). No problems with any remaining tank debris – however I should point out that the engine and tank have not been run on the road yet.

Roger

Rusty tank 01.jpg

[ranton_rambler]

My reverse electrolysis left the tank black inside but I have run 2000 miles over 2 seasons and had no problems with debris in the filter or carburettor.
Ian