B&S 10 hp vertical shaft starter question

I just completed overhauling this motor and had it bored to .030. After assembling it I tried to start it and the starter was dragging. It did manage to give it enough turn to start it but it only ran about 20 seconds before dying. The starter was dragging extreamly trying to turn the engine and running the battery down. I hooked up jumper cables to it and using the car battery it started again. Once again it ran about 20 seconds before dying. Trying once again the top of the starter broke. (It was the original B & S starter that came with the motor in 1990) I put a cheaper knock off starter on it and it dragged as well not turning the motor fast enough to start it. I pulled the spark plug removing all compression and the starter turned it much better but after putting it back in the starter would not turn it enough to start it. I tried until the knock off starter actually started smoking a little bit.

Does a B&S starter have more torque than an off brand?

Can I get a higher torque starter?

What do you guys think?
Thanks,
Chuck

B&S 10 hp vertical shaft starter question