Update:

Penetrating oil dit not help. I've decided to attack the cap. That was not so easy. The savage fuel cap is built like a tank.
There was a point where I seriously thought about explosives.

Over time I got the top off.


But there was no escape, the bottom of the cap fell into the tank.
And it doesn't want to get out anymore because it's bigger than the opening.

There is nothing to do but make a hatch somewhere in the tank,  remove the cap.
And then weld the tank closed again.

I just got my new cap in and I see what you mean.
I wil give it my best. Tanks

Edit:

Ok, that didden,t work.
I can't get a hold of it.


I have now put a ventilator on the tank to let the petrol in the tank evaporate as much as possible.

What do you think, is this, safe enough to grind the tank open and weld on the tank?

Hi Dave,

I tried but it was impossible.
You just can't see what you're doing and the opening is too small to maneuver.

I took your warning to hart and
I filled the tank with co2 from an old fire extinguisher and sawed open the tank using the drill press.



The gasoline that was in it, was very old and smelled realy terrible.As if the faeces of a mummy from the time of the pharaohs were reactivated by the olfactory fluid of a skunk x 10.


It has created a black layer in the tank as if it has turned into tar.
I don't know how long the petrol has been in it, but I think more than 15 years.



There is not that much rust in the tank I can wipe it off with my finger.
Everything is bone dry now, so I think its save to weld on it.

I just need to find a way to clean the tank.

Rust isn't so much the issue, it's the layer of tar that the old gasoline has turned into that is the problem.

I cut the cut piece into quarters to test what I can solve it with.
It turns out that diluted sink unblocker dissolves the tar after half an hour.  

I will weld the tank now. Those who are going to die salute you.

Edit: Its welded.
I used Tig with aluminum bronze. Not my most beautiful welding job, but it's closed.


If you want to prevent that it also happens to you...
Then check whether those 2 screws at the bottom of your cap are tight. Because with me they were half loose.

And so the mechanism that pull the pins in, no longer worked.

Have a nice day  

(And if it happens to you then, Make a hole right onder your Cap and tighten the 2 screws).