Take the starter to a rebuild guy. They exist. Or get another off ebay used.

So, you know nothing about starter perm mags?

its ok to say that.

There are a limited number of possibilities for orientation. Try them all. Which isn't going to happen because you've epoxied the magnetics in place instead of a dap of silicone to test things. And that's the part I know. How to find out what I don't know. Then take it to a rebuild guy. He can check why it's still running slow. Plus he'll have the part you need to fix it.

Ha, i got 2nd blown mower with same starter. it is a gear reduction style. thru a rod and the rod punched thru block and broke cast ear on starter. haha. bUT the steel case body on starter is ok so i could use it for parts. cept i sold old mower. i just wanted the new parts mower to get the starter. for giggles.

i took off starter and found broke ear then gave mower away. so, just my time, no money