Ask the Editors: From Diesel to Gasoline
Can it be done? Yep. Should it be done? Nope!
Your MULE is equipped with a 993cc inline three-cylinder Yanmar diesel engine putting out 38 lb-ft of peak torque at just 2400 rpm. Compared to the gas engine in the Mule Pro FX and Pro-FXT, the Yanmar mill is not only the more robust option, it boasts a lower cost of ownership (10-20% more fuel efficient).
While swapping to the 812cc liquid-cooled DOHC 4-stroke; 3-cylinder gas engine isn’t impossible (though it would be quite timely), you would gain absolutely nothing in doing so: no gains in performance, poorer fuel economy.
Your best bet would be to trade your MULE in on a more performance oriented side-by-side or simply make the most of your machine’s slower, work oriented persona.