Hi Dennis, have you checked the capacitor. Or capacitors if it is capacitor start capacitor run ?

The original motor was cap start with a centrifugal switch….well at least mine was equipped so.

I binned the motor in favour of a 3 phase job with a vfd.

I also bought spare belts from Beeline Engineering in Milton Keynes at very favourable prices over any other supplier ( such as Warco/Chester)

Shout up if you think I can help..

Are you on a 60 Hz supply? 1750 rpm sounds funny for 50 Hz.

I'd just replace the cap(s) with modern equivalents as a first step. The symptoms sound like a dodgy start capacitor. The motors themselves are nearly bulletproof except for the bearings but they should be fixable especially if ball races.

What sort of motor is your 2000 rpm one? A 4 pole induction motor will run at 1800 rpm max (maybe 1750 actual) on 60 Hz and a 2 pole maybe 3500 on 60 Hz. Anyway it's only 14% faster than your present motor which is negligible. As for the power, people don't seem to appreciate that power is the MAXIMUM the motor can turn out when fully loaded. It doesn't deliver any more power than the job absorbs, so if your worry is the belts breaking with more power, if you don't take heavier cuts it's no more likely than with the current motor.