New Cap and 9x20 lathemotor still won't go high speed

[ZipSnipe]

This is the continuing saga of my 9x20 lathe motor replacement from 1/2 hp to 3/4.
Well I upgraded the cap from a 40mfd 250vac to a 52-68mfd 220-280 vac(it was ranged like that). Now when I started it up I didn't have to spin the chuck to get it going on a medium speed.
But as soon as I switched the belt to the higher speed(belt is also tighter on the pulley) it would trip the breaker.
So do you think I need a bigger cap or what?

[Al_The_Man]

What I don't understand is if you purchased a 3/4 hp motor is why didn't it already come with the Cap installed?
Or at the very least the manufacturer or motor supplier should provide the size you require?
Al.

[ZipSnipe]

Oh did I mentioned I got it from Harbor Freight. I probably should just order the cap from them. A technician at Grizzly told me I need at least 60mfd 250 vac cap which I got one from an electrical place here in town. I was excited when I installed the new cap because it seemed to work better than the old one. Like I said I didn't have to spin the chuck to get the motor goin , until I switched the belt to the higher speed. Then the breaker blew again and again. So I'm kinda in the dark. Shouldn't a bigger cap give it the boost it needs? or then again I might have it wired wrong, I don't know.