It appears replacement engines for that tractor have a fuel pump-
So, I'd expect a clogged fuel filter or weak pump.
You might check the pulse line to the pump and the fuel line TO the pump for cracks.

To go uphill, the engine requires slightly more fuel. A marginal filter or pump may work adequately up to that point.

if no luck on the fuel side, might try a fresh, properly gapped spark plug...

Water or loose rust in the float bowl could be the culprit as well.

Ok I changed and gapped the plugs and changed the fuel filter. It runs just fine going up the hill until I engage the blade then it stalls out. Where is the float bowl located?

Same thing as the carb bowl.

Turning the blades also requires additional fuel.
Refer back to my first post.

This post was edited by bill_kapaun on Mon, Sep 1, 14 at 20:40