hi I've got a mighty midget two stroke petrol engine driven 200 amp arc welder and although it starts very well and the engine is spot on , the dynamo side seems not to function properly . after two inches or so of welding the machine cuts out also it has a 30 amp 240v blue socket fitted that will only light a bulb very dimly . i was wandering are there brushes or any thing in the dynamo that could be dirty ? or any thing i should look for ? the welder has stood for a number of years and looks in very good order and clean . it doesn't look like its been abused or seen a lot of service . i have looked in the top box and all wires look o.k with no sings of burning or bad contacts . any info would be most grateful . regards Richard 
