My D2050 has always started hard. It always requires lots of glow plug time, pumping the throttle, and lots of cranking, even in the summer. It cranks like it's laboring even with a full charged battery. I'm wondering if it could be a starter problem. The fuel filter is new and fuel flow seems okay. After it starts it runs okay and does not smoke. I have no manual so I don't know of any adjustments that might improve starting. I don't thing I should even need the glow plugs in summer - right? Any ideas?