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I am going to pull a crank to have turned to 3/4. Its on a Briggs 6hp, its as now tapered, 4-1/4 long and is .872 in diameter. It has a 1-1/4 schoulder coming from the case to the machined shaft. How far should the shoulder extend beyond the seal to run a TC-2. How long should the 3/4 shaft be...