Hi,
The majority of people don't realize how costly a simple lawn mower is in terms of replacement parts. The cost of a new B+S Carburetor for this twin is listed at $197.00 to$220.00. A new engine is $1500.00 list. All similar Koehler's and others are in this same price range 0r more. A 17.5 HP for a MTD is nearly the same. When I was into repair I was going to rebuild a blown Sears engine which I received, the part cost exceeded a complete new engine by $300.00. I had a recent model Ingersoll air compressor for repair, a guy let it run low on oil and kaput! The cost of a new one was about 800 to 1K. Part cost was $800.00, no labor. It is an unfortunate situation as 90% automated machine work on die cast parts! End cost is probably a third or less of the retail price. My son's Big Cadet 2000 had a simple oil leak on the crank, that engine if not repairable would have cost $1500.00. A local shop here is really rip off place for parts, so you have to hunt a reasonable part cost and do your own labor!
Yep, everything comes with a price. I do this every day. What you may not know that your local shop knows is how these carbs work. A couple of tips given could save you real money. They would likely charge you an hour or so of labor and the price of a kit while using a few select o-rings and seals and the result is pretty much the same if you choose to google a 796227 carb and install it yourself with a little bit of care. Or put a clone carb on, kick yourself, buy in again in an OEM and possibly learn from your experience for the next time. By now the flange on the plastic manifold is warped. What is money any way? The local shop owner 2 streets down that coaches kids softball and has a kid in their second year of college. Round and round and round the world goes. Enjoy the time you are here and live in peace.