Hi Brett, I do agree with grumpy a second hand Briggs in good running order, may be the answer. There must be some out there...2.5HP, 3 Hp and 3.5Hp and all will fit your machine with a little effort.
Here's a pic (sorry about the quality, its the only one I have)
![[Linked Image]](https://www.outdoorking-forum.com.au/forum/uploads/usergals/2012/10/full-1147-8511-scan0001_medium.jpg)
If you could source a Briggs, and there is a problem with the output shaft size, you could replace the engine side clutch housing with the 5/8" model ; it is available in the online store and will fit the Model 33 as they both have the same cutter clutch. See
HERE