Just wondering why do you think the engine is too small? My mower is 22HP with a 61 in. deck and has all the power it needs. That mower is only 10 more inches with a diesel engine. How much power would that engine have? Also I just cut lawn with mine for the most part but even when I get in the high stuff it doesn't lack in power. I repair them not operate them so I am far from a expert on this matter. Also I though that that mower had a lot of hours on it and he will be working it hard.