I worked on refurbing my backup compressor (oiled twin tank Hitachi) yesterday, due to making air slowly. One of the reed valves was corroded/worn through, the unloader line had a loose connection at the tank exit, and the shutoff diaphragm was leaking. Got that done, but it's not turning on very well - I think the unloader valve is stuck too :/

I'd swap that Makita for a fresh one if you're still within the return period.