Small Engines (Lawn Mowers, etc.): To disable B&S speed governor?, horsepower requirement, briggs stratton

Question
I can't remember if I have asked you this question before. I am having a problem getting sufficient lift in my hovercraft because the 20-hp Briggs & Stratton V-Twin (Vanguard) is not able to spin 3,600 rpm under load (with fan fitted). Max rpm achieved is 2,300.

Without any load (no fan fitted), the engine spins 3,600 rpm all right.

What can I do to achieve 3,600 rpm with the load(with fan fitted) and how do I do it?

Answer
What is the minimum horsepower requirement for the fan?

If you can get 3600 rpm with no load then the engine is probably running fine.  Have you made any other governor adjustments besides adjusting the governor spring?

You can try putting a stronger governor spring on but I'm still not sure the engine will have enough hp to run the fan.  If you completely disable the governor I'm afraid severe engine will occurr.

Let me know.
Eric