Craftsman 54" Lawn Tractor ODD Popping, Loss of Power under load - Please Help

[Mark97213]

Greetings all. I'm stumped as to why my Craftsman DGS 6500 54" lawn tractor is running just fine... until you engage the lower cutting deck. Once engaged it seems to run fine but at a little loss of power and then popping, stumbling ensues as soon as the blades are engaged but, it is intermittent. I assumed the deck spindles were binding up or there was a build up of grass but that was not the case. Could a failing electric clutch be causing the intermittent problem?

 

[bertsmobile1]

Run the mower for 5 minutes then stop it & remove the dipstick.
If you see wispy white smoke then your head gasket has blown .
Another symptom is a bad backfire when you shut off.

 

[Mark97213]

Run the mower for 5 minutes then stop it & remove the dipstick.
If you see wispy white smoke then your head gasket has blown .
Another symptom is a bad backfire when you shut off.

There is no smoke at all in the dipstick as you suggested and there is no backfiring. Still has good compression in both cylinders, replaced both coils a couple years ago. Starts right up, runs as strong as it ever has until the deck is engaged but even then, you can't notice any change until you start cutting.