My HR215 was surging when it was not under a load. When I engaged the blades it quit surging. So I took carb apart and removed the jets in carb and the needle valve on the front of carb. I replaced all and now it is missing when running. It can be hard to start now also. Any ideas how to fix this missing problem?
It can be a challenge to properly clean a carburetor, and even then, getting all the gaskets, spacers, and guides all back on absolutely perfectly is critical. A tiny vacuum leak around any of them can cause starting/surging, as will an incorrectly installed gasket. It many cases, it can be less frustrating to simply replace the carburetor. For the HR215, list price for a new carb is $43.
You need to make sure the choke is properly closing, the throttle cable is adjusted correctly, and of course, don't forget a clean/new air filter. Any/all of these can cause poor performance or hard/impossible starting.
A shop manual is invaluable for this level of repair; Honda sells paper copies on eBay and Amazon with free shipping.
Honda Power Equipment Shop Manuals on eBay
Honda Power Equipment Shop Manuals on Amazon
Here's a sample page for the HR215: