Small Engines (Lawn Mowers, etc.): Mower backfiring, mower deck, exact model

Question
I have an Craftsman 50" cut riding mower.  I have performed the usual maintenance on it - spark plugs replaced, fuel filter replaced, oil filter and oil replaced, etc.  With the mower deck engaged, it will back fire and seem to want to bog down.  I know I don't have model number but what am I missing in the annual maintenance that I haven't done.  Thank you.

Answer
Diane
If the problems going uphill began after your tune-up then it is most likely related to the fuel filter or air filter you used. If the tractor is not running badly or hot at any other times, the issue is not likely to be related to the spark plug you used.There are a couple different engines that the same problem.Some are pretty sensitive to any added restrictions from an incorrect air or fuel filter, so a universal or incorrect filter could be limiting overall horsepower which is showing up under the added load on hills.
You might want to try installing the recommended filters for your exact model to see if that improves matters. You can find the parts recommended for your particular model at theSears PartsDirect website.
If the problem was already present before your tune-up, then you might have an issue with the drive belt or brakes, either due to wear or mis adjustment. Or you might have an issue with the throttle/governor settings or even an issue with excess engine wear.
If the uphill problem was already present before your tune-up, then you might have an issue with the drive belt or brakes, either due to wear or mis adjustment. Or you might have an issue with the throttle/governor settings or even an issue with excess engine wear.
make any carburetor adjustments.