The aircraft was topped off to 540 pounds of fuel at a tach time of 3908.8 hours and subsequently flown to a tach time of 3911.4 hours. The aircraft was not fueled and subsequently departed for Portland, returning to Boise after a tach time of 0.4 hours due to the right main landing gear's failure to retract. The PIC then opted to depart and fly nonstop to Portland with the gear fully extended. The aircraft was not fueled subsequent to the 0.4 hour flight. The aircraft departed a second time for Portland at 1808 hours PDT and later reported consuming 110 pounds/hour of fuel. At 1936 hours, and after discussing available fueling facilities with Redmond FSS, the PIC diverted from his route of flight towards Redmond for fuel. At approximately 1950 hours the pilot radioed to Redmond FSS that he had run out of fuel and was executing a forced landing. Dusk light conditions existed during the forced landing and the PIC did not see the canal and dirt bank in his landing path until after he was committed to the landing site. During the landing roll the nose gear struck the dirt bank and separated and the aircraft nosed over. The tach time at the accident site was 3913.6 hours.