Replacement engine options for a 720K?

[NorthBama]

NorthBama...spot on.Don't know why they named them courage.where's the courage if you can only do 30hrs...russ

Have seen two one was on a nice Husqvarna machine with 60 hours

 

[2ooter2]

It will either be a 1" or 1 & 1/8" and most likely the former.
Your only real problem will be the PTO height.
If you don't mind a bit of metal work you can get superceeded Briggs around that size for around $ 800 with a warranty .
Kohlers go about 20% more
Add another 20% for Kwaka and
Add 10% for a Vanguard

The biggest headache from changinf brands is finding a muffler to fit or modifing the existing one to fit.
These are specific to a particular mower and in many cases the only difference from one spec to another

Since your mower is a 20yr old 720K it's a Command, not a Courage & it probably has the 1-1/8" diameter shaft x 3-11/16" long. The internal thread holding the PTO on is probably 7/16", but if it's 3/8" just change the bolt. Get another Command engine in the HP of your choice up through 27hp, all your accessories will exchange as long as the replacement engine has the same style air filter.
I just replaced a '95 718K engine w/1700hrs that was doing about the same as yours(leaking oil, running hot) with a rebuilt 2000 725cc 25hp Kohler with the flat air filter and an oil cooler from this guy http://wichita.craigslist.org/grd/5741213718.html for $800 plus the cost of the trip to pick it up.
It was a direct bolt-in, used my old muffler & heat guards, everything else came with the new engine since it was an actual Grasshopper engine. Contact the guy, he will ship, it's about a half price alternative to a new engine.

 

[Grouse09]

Browncoat, I am curious. What did you do/decide on?