John Deere offers a full lineup of generator drive engines, from 2.4L to 13.5L that includes engines certified for Tier 3, Tier 2/Stage II, and Tier 1, as well as non-certified engines for specific applications. All John Deere generator drive engines feature replaceable wet-type cylinder liners, a heavy-duty crankshaft, and mechanical or electronic fuel systems that make the engines durable and reliable.