Small Engines (Lawn Mowers, etc.): old lawn tractor question, sprocket teeth, drive sprocket

Question
I'll try a second time.
I have an old Craftsman rear engined, chain drive, lawn tractor number, 502.254170, that I converted into an electric cart.
The question is how tight should the chain be?

I ask because I run the cart through the original transmission and when going down hill I get a clunk, clunk, clunk.  Can't tell if it is coming from the transmission or the chain is slipping. On lever ground or going up hill, no clunk. I can push the chain down about 1/2 inch.
Thanks
Bill

Answer
Hi Bill

Try adjusting chain tension to about 1/4 inch which about 1/2 of what you have on it now,
but check gearbox sprocket for broken teeth, and the final drive sprocket for broken , worn or hooked teeth , also check the chain for excessive wear, it could be riding over tops of sprocket teeth when loaded

the other cenario is you have a gearbox with damage to internal gears , but more likly  worn chain and or sprockets  - i suspect  transmission is a peerless 700 series  with  a 100 series differential  which has the final drive sprocket on it  ( to replace it you will need to remove differential from tractor unit  ( its bolted on with 4 long bolts through differential casing  

here is website for parts breakdown

http://www.searspartsdirect.com/partsdirect/part-model/CRAFTSMAN-Parts/Riding-mo

select drive system , and diagram will open up

hope this helps your situation

cheers paul , have a good day