It's not hard for a engine designed to put put out over 100 HP at 6000 RPM to live at under 50 HP limited to 2500 RPM. All the starts and stops are the worst thing it sees. On propane this is not a big issue as it would be o n gas. Amazing the Mitsubishi starter is still running.
Just broke in. I worked for a dealership in the SF bay area and I saw many of the high use clients Nissan engines go 35,000 hours running propane and straight 30 Delo. A maintained forklift engine has an easy life.