Great video! I splurged on a NOS Walbro for my 5645, and it worked perfectly, until it didn't! There are some very small passages inside the body that are difficult to clean, so I opted for a new carb, instead of repairing the original. Unknown to me, my fuel pump was very dirty with sediment and corrosion ( I think the machine spent some time submerged) and I neglected to open it up prior to starting with the new carb, so another lesson learned. For the fuel pump fix, I used some gasket material that degraded in gas, so the new carb got plugged quickly and I was back to square one. Now I'm popping out welch plugs and cleaning in the ultrasonic cleaner. The 5645 has a rope start, so fast starting is a necessity! Thanks for sharing, I will be interested to see how reliable the Chinese carb will be.