81 Marathon, loose belts

[frodrummer]

I am sure this has been covered many times. However, I am having issues with loose belts. Upon reinstalling the original belts, both belts have a lot of slack. The starter belt is so loose that the starter just spins, and won't grab the belt. I know that there is a mild amount of adjusting possible with the s/g, but it's adjusted out as far as it will go (or at least I'm assuming). It is still really loose. The drive belt seems excessively loose as well. I do plan to replace both belts in the future as they seem to be "good enough" for now. But I want to eliminate any possible adjustment errors on my part so as to not run into this same issue with new belts. Anyone run into this before? I haven't measured the belts yet, but I do find it hard to believe that they have stretched to the point of being too loose on the highest tension setting/adjustment possible (at least on the s/g). I understand that the drive belt will have some tension, but I won't know if it is actually too loose until I get the cart running, and can't do that until I get the starter belt tightened up. I'm at a loss here.

It may be worth noting that I have never previously driven the cart. It was given to me in non-running condition. As such, I was not able to check the operation of the belts before the rebuild.

[kyerik]

Check your motor mount bolts and engine cradle mounts, if they are really loose, that could make the drive belt loosen up.

The alternator belt should be tensioned with a tensioner bolt that pushes the alternator away from the engine- maybe someone put a belt on it that was 1" longer than it was supposed to have.

[BrewCityMusic]

Your drive belt is SUPPOSED to be loose when sitting - so loose in fact that it can be rolled right off the clutches by hand (when the engine speeds up the sheaves will close on the drive clutch and tension it) - the starter has the main pivot bolt(s) (I've seen both styles of mount on the Marathons, single OR dual bolts) and a third bolt on a bracket in the rear - if this one is adjusted all the way then I agree, you've likely got an incorrect belt on there

[frodrummer]

I am settling on incorrect belt as well. I've eliminated everything else I can think of. I went ahead and ordered new belts, just to be safe. I should be up and running for the first time after turkey day. Thanks for the input!