That engine was a cows vagina. It takes engineering integrity to make a a good large displacement 4 cylinder engine. This is a quality that Mitsubishi don't seem to have. Their engines have additional features like 'crank walk', premature ring and bore wear, premature valve stem seal failure, cylinder head failures.
They are nice and smooth for the first couple of years and then they smoke, rattle and vibrate as the premature mechanical wear takes its toll.
Very poor fuel economy. They would often use more fuel than a 6 cylinder when asked to work hard.
I wouldn't even use one on a ride-on lawnmower.