Update after a bit of usage:
The extra HP is just what this mower needed. Runs mostly on half throttle (let the governor do it's thing), unless in really heavy going. This motor does not die in the bum like the other little one did - it has enough torque to maintain the blade speed whilst the governor kicks in.
One of the biggest complaints of the "non-mulching" brigade is the lines of noticeable cut grass left by the mulch mower in heavy going. Keeping the blade speed up is the key to minimising, or even eliminating this problem.
The only other issue seems to be a design one - my son-in-laws' Victa Tornado (same motor, but different cutter setup - "turbo" disc and four blades)seems to make much easier work of heavy stuff than the bar blade on the MTD.
Removing the mulch plug and using it as a 22" utility mower is a complete revelation with this motor. I can now go through 4-week growth kikuyu at a fast walk, where before, it was ... push ...wait for revs to come back up, push ... wait .. etc. Saves much more in time than the little bit of extra fuel it uses
