The SK90 carburetor from http://www.kangkeusa.com/ will work with your TH 75. The SK70 and SK80 probably have the same carburetor too, but I know that the SK90 will work. I have used one on my TH75 since last season when I broke the HS needle off the carb on my TH75. Tower has had the carburetor and parts on backorder for decades. I had an SK90 available and the carburetor bolted up and worked flawlessly. The price is right too!