Hi Phil.
Before you get one of them "volt thingies" as you say, try this.
Without getting into technical mumbo jumbo there is an old "bushies" way of testing whether your generator is in some sort of working condition.
Pull it out and on the bench.Connect a battery to it.If its in any working condition the generator will spin like an electric motor (which it sorta is) however it won't turn very fast as its not designed to work as an electric motor as such.
Its been so bloody long since I've done this I can't remember the process of connecting to test but gennies are tough so you can't really bugger it up...................you will just get a lot of sparks if you connect wrong
.
If your starting problem is a sluggish starter then your starter bushes (not brushes) may need replacing as the armature will "pole" (ie:- rub the magnets in the starter case) and this slows the starter.Worn BRUSHES could also give a slow starter.There are other things that will slow a starter but these are probably the most common.
Your time costs nothing so if you can test things yourself then its worth the time to try.
With any problem I always test the simple, low cost items first then move up to the higher cost replacement items.
A lot of times it can be low cost things causing the problem.
No use rebuilding a starter or generator when the problem was, say, a dirty battery connection ( yes, I've done it
)
Good luck and hope this helps,
Terry.