On December 14, 1995, at 0800 hours Pacific standard time, a Cessna P210N, N4598K, collided with a concrete footing after an on-ground loss of control during takeoff from runway 25 at the Nevada County Airpark, Grass Valley, California. The airplane was substantially damaged. The certificated commercial pilot and passenger were not injured. The airplane was being operated by the pilot/owner as a business flight under 14 CFR Part 91. The flight was destined for Novato, California. Visual meteorological conditions prevailed. An instrument flight rules (IFR) flight plan was filed, but not opened. The pilot aborted his first takeoff because the engine produced only 25 inches of manifold pressure, and not the normal takeoff power of 38 inches of Hg at 2,700 rpm. The pilot turned the fuel boost pump switch to the low position and was able to gain 3 more inches of manifold pressure, but again not full takeoff power. The pilot attempted a second takeoff. At 80 knots the pilot rotated the airplane. The airplane became light on the landing gear, at which time the landing gear began to retract. The pilot immediately saw the landing gear handle was in the up position and moved it to the down position. The main left gear extended and locked. The right main gear and nose gear did not. The airplane settled to the runway and the pilot aborted the takeoff. The airplane veered off the right side of the runway and struck the concrete footing of a runway edge light under construction. The airplane continued another 50 feet and slid down an embankment. The airplane checklist reminds the pilot to check the position of the landing gear lever before starting the engine. The engine was examined by an Federal Aviation Administration aviation airworthiness safety inspector on January 3, 1996. During the examination, there was no evidence of mechanical failure or malfunction found that would account for the 8- to 10-inch drop in manifold pressure. The engine was not capable of being run due to accident damage.