I can answer one of these. Not highlighted in the owners manual but believe you'll find it in there. Loosen the nut on the drive engagement cable where it attaches to the handle go make the mower go faster - should help you up the hills.
Answering my own question here. After figuring out that the loose and inappropriately named lock nuts were 11mm I bought a narrow open end wrench and some lock tite and was able to tighten them down. There IS very little play to work with in that area but it can be done. The wheel assembly is tight against the frame now.
Maybe a 11mm wrench should come with the mower.
Still waiting for an answer on this a week later. Seems like the most basic of a customer support type question.
Update: Got my answer but had to go to the Briggs & Stratton website. They have tons of models and the B&S model name is not the same as the Husky name but eventually found and ordered the part there. They do provide diagrams there which are not great but usable.
This may be it. There is a spring on the opposite side from where the spark plug goes in that helps control the speed of the engine. It could be bent, stretched, or loose. I got around some bushes with my HU775L and suddenly the engine speed went from full power to an idling speed. Finally figured out the spring got bent & stretched. Sort of fixed it with needle nosed pliers. Came here looking for a replacement spring and a GOOD diagram of the engine parts.
Still looking for that info.