not battery problem the brushes and or the bearings in motor or shaft are heating up and binding you can try lubing the bearings on unit so that their not dry as to the brushes if worn down an are heating up they would need to be replaced ---also check prop that no ebris is around shaft or behind the drop causing a drag
sounds like a loose or bad connection on the throttle switch will need to open the control tiller and check connections if you have a meter ohm out the wires at the connector and switch to make sure all connections are good this is a bit involved and I recommend doing on a bench not in the boat If you need more detail just ask You know this sucker comes with a 2 year warranty right ! If you need further help, reach me via phone at https://www.6ya.com/expert/richard_b70d968cd1a1d293
what do you consider a lot of play
1/2 inch, 1", .02",040" or what
talk with a service agent for the equipment to get the exact amount of end play permissible or down load a workshop manual for the equipment
