If you have the engine set per the instructions, you have the initial settings correctly-set. If the engine won't start, you'll need to make sure you have a good glow plug, a good glow plug battery, and are not over- or under-priming the engine. If the engine's had a bunch of running, you may have to check the piston/cylinder fit. Hard running with dirt ingestion or an overheat or two can cause a bad piston/liner fit, which means that the engine's compression is shot. You may need to rebuild the engine.