Deere 1209 MowCo -- Tighten reel drive chain?

[mattv1]

Hi Everyone --- I have a manual on the way....but I'm having trouble with the chain that drives the reel on my 1209 MowCo. It's quite loose, so loose that i can take it off the sprockets with my bare hands. When I get into thick hay, it jumps off. I see an adjustment for the space between the rollers, but i don't see a way to adjust the tension on the chain. Does anyone have words of wisdom?

thanks!

 

[Tx Jim]

What is your Mo-Co's serial number? If it's after 285001 - one can loosen nut(parts key 1) ans slide bolt holding sheave back in the slot in the bracket(parts key 8B). If earlier model I'd suggest to install new chain.