The crankshafts are not all identical or interchangeable. You need a crankshaft that matches your specific engine. There's two basic types, regardless if it is supported by (one or two) ball bearings or plain bearings only:
1. The old style crank has an extension that the old style starter clutch rides on (the all metal starter clutch/ratchet with the balls inside).
2. The new(er) style crank lacks this extension and uses a cup starter on the crank/flywheel. The starter mechanism in the blower cover is totally different and uses plastic pawls that deploy to engage notches formed on the inside of the steel cup, and this in turn turns the engine over.
The bearing style has to match too, or you may install a ball bearing crank inside a plain bearing block, which won't work.
Please post the engine code numbers inscribed on your blower cover. The number for a 5 HP usually starts with 130XXX. Hopefully it is the original blower cover, sometimes they are not. With those numbers, one can find an illustrated parts list that will depict which crankshaft and/or part number is correct for the engine.
Post good photos of your current crankshaft too so the forum can determine if the threads can be restored or if it is a lost cause.