Cessna 441 pilot reported experiencing a runaway power setting while taxing for departure; resulting in a taxiway excursion and hitting a taxiway light. The pilot taxied back to the ramp.

Narrative

Chain of events The aircraft that I was piloting experienced a runaway power setting resulting in a brief taxiway excursion. While conducting the first flight of the day a 'manual mode check' is to be completed by advancing engine speed and switching the fuel computers off; then advancing the power levers slightly to establish manual control of the engines. I followed the steps outlined in the Manual Mode Check checklist and advanced the power levers one by one. The left power lever functioned normally with a slight rise in torque. When I slightly advanced the right power lever the right engine ran up to nearly full power. Even though I applied full brake and full reverse to both engines the right engine stayed at a high power setting pulling the airplane away from the taxiway centerline and towards a taxiway sign and drainage ditch. I switched the fuel computers back on restoring control of both engines and steered away from the ditch and sign obstacles. Unfortunately I was now in unavoidable path of a taxiway light. I elected to steer directly at the light as any other path would have put the light into a propeller. The nosewheel strut made contact with the taxiway light and I was then able to steer back to the centerline of the taxiway and notified tower that we would be returning to base. The aircraft sustained no damage. Human factorsThe entire event unfolded in the matter of mere seconds. If I had turned on the fuel computers a second earlier; I may have been able to stop before encountering a light. Nevertheless; my perception was that brake and reducing engine power would rectify the situation; and when it did not I had already lost a valuable 1-2 seconds. A contributing factor was the short taxi instructions that I had received. When taxiing from the ramp at ZZZ to Runway XXL at [Taxiway] 1 there ends up being only a very short taxi on one taxiway. This leaves suboptimal; but still adequate room to conduct first flight of day checks.