"cj" wrote in message
...
Hi
sounds like a great excuse to learn about generators (you can't make it
any worse)
Basically a generator is a spinning coil (or coils)of wire which spin in a
magnetic field usually generated by another coil of wire.( I'm sure you
knew this).
But did you know the field coil is usually DC whilst the armature is
producing AC.
Most generator have a rectifier pack or voltage regulator connected to the
field and these often go faulty.
Another common fault (with long unused sets) is sticking brushes.
Yes they DO have brushes these bring the AC output off the armature and
can stick in their guides giving symptoms as you describe.
Find the brush gear and measure the voltage with the set running also
check the field voltage out of the regulator.
Oh of course check that the field windings are ok.

Just a few pointers to get you on your way

ALL of todays modern 3000rpm generators, and definately the throw away style
2 strokes use a spinning DC field and the AC power comes off the stationary
armature- i.e. NO brushes.

The OP probably has a shorted field or more likely expired diodes (yes,
very cheap and nasty) on the field coil. You will need to strip the spinning
part out of the generator and replace the diodes, and check the resistance
and insulation of the coil.

It's far from unheard of in this league of machine for the windings to move
slightly or there be sufficient 'slop' in the bearings for the field coil to
contact the case or armature and wear it away / short it.

Tim..