Z665 misses badly when the mower deck is engaged

[na svt]

The engine runs very smooth when the deck is not engaged but as soon as the switched is pulled it misses badly. Any ideas?

 

[bertsmobile1]

Got lots of ideas.
Most will be irrelevant to your mower, engine & problem
So if you don't want me and others to have you running around like a headless chook
please post you full model number and engine numbers
and :welcome: