"HR215" covers a lot of ground without other identifying information (numbers/letters). Generally speaking, what you will find is:

The early HR215 "Masters Series" was a 4.5hp with cast aluminum deck, BBC, and red metal blower cover with a red cover for the oval "auto style" air filter. This motor has ball bearings on both ends of the crankshaft. This came with either a 3 speed or hydrostatic transmission and both had shaft drive.

The next HR215 "Masters Series" was a 5hp with ball bearings only on the top end of the crank, has a red plastic cover over the motor with built in fuel tank, and a rectangular (Briggs style) air filter inside a black box on the side. It also has a cast aluminum deck and BBC. I have only seen these units with a hydrostatic transmission. shaft drive.

There were some steel deck HR215s- some had BBC and some were zone, all had 4.5hp engines, and were either push or S/P. I have not actually seen one of these units.

The HR215 "Harmony" series- (HRM= mulch, HRB= bag) has a lot more variations- but all have a gray plastic deck, either a 4.5 or 5 hp engine, has a red plastic cover over the motor with built in fuel tank, were either push or had a two speed, three speed, or hydrostatic transmission- with BELT drive.

Very few parts for the poly deck units will transfer over to- or from- the late series cast deck "Masters" HR215s because the belt drive system on the poly deck changes so much. The only wear related parts I can think of are the carb, muffler, front wheels, and maybe the recoil starter.

My point to this long post is that if your looking for used parts, you need to know what model you have before you drive across town to look at a donor mower. And the best way to figure out what you have- so you can cross reference what works- to to use the link I am providing.

I must state here I am not affiliated with this website or business in any way, but I have repaired a number of HR215s and am lucky enough to live just a couple of miles from them, so they have been a huge help to me.