I have a 8hp tecumseh snow blower bought last year. Now when I go to use electric starter and push the button it makes a loud grinding noise and will not start. Any suggestion what it may be ? HELP!

Need help IDing a carb. I have a Tecumseh SnowKing engine that I believe is a medium frame 6hp. The original engine had a cable operated throttle control and a multiple position choke control. When that engine died of old age, [and a rod through the side of the block] I went to a local small engine shop and priced a new motor. While debating putting that amount of money in an almost 40 year old blower verses purchasing a new blower, the owner showed me several used engines. I got a very good price on an almost identical engine, the main difference was that the replacement engine has a newer[?] style carb and shroud. The carb features one lever, up to choke, down to run. There is a small on/off electrical switch sticking straight up through the top of the shroud. No provisions for a throttle cable. You start the engine up and it runs WOT controlled by the govenor. The carb has a plastic choke arm/shaft/plate that has broken. The end of this plastic arm engaged a metal arm that sticks through the shroud. There is an o-ring sealing the shaft and the plastic shaft is held in with a small L shaped bracket attached with a single screw. I need to replace that plastic piece. When I bought the engine the recoil housing was missing it's ID tag. I have no model or serial number to work with. There is a number stamped in the top of the carb 400 2f28, and the bottom of the float bowl has Lauson Power Products Grafton Wis. USA stamped on it. Can anyone give me something to go on? I can't order parts without a engine model/serial number. I will monitor this posting or answer PMs. Can email photos. :wall: :wall: :wall: