I think there is more going on than just the belt tensioner arm or bolt loosening and slipping.
I have never had a problem keeping that tight on any of my engines/vehicles, and I never over tighten them, they stay put with normal efforts.
An example of how easy it is if the rest of the system is in decent shape:
Friend of mine had a model A ford car, I commented that his fan belt was loose, when I poked it the whole generator moved, not tight at all... He said , "It's OK, the weight of the generator keeps the belt tight enough" And it did, it was summer time and he drove the car all over the place, including over the mountain between my place and his, and even going slow off road on the 4 wheeler trails. It never overheated and the battery stayed charged.
I'm not saying you should leave the generator/belt slack, only that this is a simple thing, and that part of the system is likely not the real problem. Something else must be going on to complicate and confuse things.
Grigg
