Sluggish Dynostart

[Dudley Smith]

The Dynostart on my AV105 is becoming increasingly sluggish. Despite two fairly new and well-charged batteries, it failed this morning to turn the engine fast enough to start. It is a very cold morning and my engine has highish compression, but my memory is that it used to be a bit more vigorous. I have certainly started the car in cold weather before.
What should I check first? The brushes seem to be in good order and sliding in their holders, but I have no idea when the commutator was last cleaned. Could it be a build-up of carbon dust between the commutator segments?
Any advice gratefully received.
Dudley

[Guy Gregory]

I would use compressed air and blow it through and also clean the segments. Make sure the brushes are bedding properly and free in their holders
Cheers Guy