The magnums are pretty good units. At one point I had 60 of the mlt3060 in my fleet. Had the D1105 engine in it. Out of all those units, I only had one engine grenade at 1,000 hours. The rest were pretty much bulletproof. If it quit, check the fuel filter, and radiator. Was usually either low on coolant, moth plugged fins in the radiator, or someone had some bumb fuel in it.
Some of them had upwards of 15,000 hours on them before they were sold. The 3060 only had the 6kw gen end instead of the 8kw.
Keep the oil changed at 250 hours if your using it continuously. Make sure and keep the radiator cleaned. The Moths get drawn in between the light, and the diesel smell. Use to have to back the pressure off on the shop pressure washer and steam clean the radiators periodically.
Haven't had any experience with the tier 4 engines. Shouldn't be an issue since it's only 13hp so no regens or particulate filters.
Should be a tag on the unit with generac's number on it. If its an older magnum, the number on the tag is still in service. You can call them, ask for technical support and see of they can email you a pdf of the operators/ parts manual if you don't have it.
Parts breakdown for the engine will only cover the dealer add on parts such as fuel solenoid, shut down sensors, and light maintenance parts.
Parts breakdown will cover all other aspects of the unit from frame components to breakers, light assemblies, mast parts, winches, ect...... If it uses LED's for the lights, they may be dealer only. But check with an electric supply before paying dealer prices and shipping.
The mast lights for the 3060's that I had, took the same bulbs and sockets as the street light at the end of my driveway