Hello There,
Thank you for the advice, the battery seems to run out of steam quickly it,s a 36amp hour, fairly new. As the beastie still has a generator and has only been getting short runs, having no roof and with the duff weather we have been having, maybe the battery is not getting charged up enough. The starter only seems to jam when cranking power is down.
I am going to whip the starter out later and have a look at the pinion etc. Crossing my fingers.
