Troy built bronco slows on small incline

[pawandmaw]

I have a troy built bronco model 13aj609g766, engine is a 18.5 briggs 31p777 type 0293e1. I replaced fuel line, put on pan cake gas filter. New nikki carb. New motor pulley due to the grass was not being discharged quick enough after replacing deck belt. The left side deck spindle bearings froze up and started all this work that also was replaced.
Now the customer says the mower runs great on the flat and up the large hills no problem, but the small hills it runs real slow. What is the problem now???
Thanks Paw

[KE4AVB]

Kinda strange that it is having mid range load problem.

I assuming the the running real slow is a motion drive problem. Check your variable speed drive belts especially the variable speed to transmission belt for excessive wear.

Or is it an engine problem?

[Deere2me]

I have a troy built bronco model 13aj609g766, engine is a 18.5 briggs 31p777 type 0293e1. I replaced fuel line, put on pan cake gas filter. New nikki carb. New motor pulley due to the grass was not being discharged quick enough after replacing deck belt. The left side deck spindle bearings froze up and started all this work that also was replaced.
Now the customer says the mower runs great on the flat and up the large hills no problem, but the small hills it runs real slow. What is the problem now???
Thanks Paw

Did you use a new EXACT replacement part # for the pulley? Same dia/size ,etc.? Could be a belt slippage issue.