The message
from "MartinF" contains these words:

Hello all

I have just inherited a very old Sheen brand paraffin flame gun with a hood
and wheels.

No instruction manual of course but I relied on my Boy Scout prowess with a
Primus stove.

It seems that you have to heat the paraffin filled coil with the fuel
soaked asbestos wick until it reaches a suitable working temperature.

After filling it with paraffin and soaking the wick with fuel I lit it and
pumped it up to 20psi with the fuel valve shut.

When it started roaring away. I opened the fuel valve and started to burn a
patch of weedy ground .

However after about 20 minutes it "goes out " and a huge cloud of unburnt
vapour pours out.

I have taken out the nozzle and cleaned it out but it continues to go out
after 20 minutes.

The pressure is kept around the 20psi mark .Should it be higher or lower ?

I bought mine secondhand 20 years ago; they are almost indestructible.
I think I obtained an instruction book from the manufacturer but it's so
long ago I can't remember. (Excellent cheap postal spares service btw).
You're right, it's just like a primus stove so if you can work one of
those you'll soon get the hang of the flame gun.

You've got the pressure too low. I pump mine up to 30 before lighting.
Release the fuel valve just enough to soak the wick well and close it
again. Point the gun away from the wind, and not towards your fence,
shed or car. With the fuel valve only just shut, light the wick, then as
it catches, very slightly open the fuel valve. If flame leaps 10 ft, you
opened it too far. As the coil begins to heat, the beast begins to make
panting noises.

Once it has reached operating temp ( beast begins to roar) I pump it up
to 40, and adjust the fuel valve again so that the flame is pale, short
and fierce. As you're working keep an eye on the pressure valve and
pump it up to 35 or 40 again when it drops to 25.

With green weeds the object is not to incinerate them on the spot. A
quick pass explodes their cells and turns plants very bright green.
Within a few hours they wilt and in a week will be dead and dry and have
shed any seeds. Then is the time for a second pass to burn off the
debris, which will also kill the seeds.

I use it till it's empty to avoid storing it with fuel inside. Remember
to release the pressure (cautiously) at the fuel inlet on top, when
you've finished. Keep a bucket of water ready before you start, just in
case; and beware of plastic drain covers, hosepipes etc :-o.

HTH

Janet.