Narrative:

I was attempting to restart my C175 after fueling. The engine would not turn over and acted like it was vapor locked. I got out of the plane and left my brother (student pilot) in the plane and attempted to manually turn the propeller to relieve the pressure. It rotated approximately 20 degrees and then kicked back due to the excess pressure pulling the blade out of my hands. It kicked back then reversed itself; striking my hands with the blade. After this occurred; the engine started without the starter button being pushed. The master switch was on at the time. My brother's hands were clear (in the air) at the time. He did not activate the starter. I did not expect the plane to start and was not trying to propeller start it. I was just trying to relieve the pressure from the vapor lock. My hands got injured during the incident. I believe it happened during the kick-back prior to the engine starting. Even though the master switch was on; I still believe that due to the vapor lock that I would have still been injured when it kicked back. I followed the procedures I was taught yrs ago in clearing vapor lock. I believe that my injuries were caused by the excess pressure in the vapor lock because the propeller got pulled out of my hand when it kicked back. I believe what caused the aircraft to start was also the relief of the vapor lock. This could have been prevented by having the master switch off; but I was not expecting it to start. I will have my aircraft checked out by the a&P to check for any ground issues to see if that may have been part of the cause.

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Original NASA ASRS Text

Title: PILOT OF CESSNA 175 IS INJURED WHEN ATTEMPTING TO CLEAR A VAPOR LOCK BY TURNING THE PROPELLER BY HAND. ENGINE KICKED BACK AND STARTED; STRIKING HIS HAND.

Narrative: I WAS ATTEMPTING TO RESTART MY C175 AFTER FUELING. THE ENG WOULD NOT TURN OVER AND ACTED LIKE IT WAS VAPOR LOCKED. I GOT OUT OF THE PLANE AND LEFT MY BROTHER (STUDENT PLT) IN THE PLANE AND ATTEMPTED TO MANUALLY TURN THE PROP TO RELIEVE THE PRESSURE. IT ROTATED APPROX 20 DEGS AND THEN KICKED BACK DUE TO THE EXCESS PRESSURE PULLING THE BLADE OUT OF MY HANDS. IT KICKED BACK THEN REVERSED ITSELF; STRIKING MY HANDS WITH THE BLADE. AFTER THIS OCCURRED; THE ENG STARTED WITHOUT THE STARTER BUTTON BEING PUSHED. THE MASTER SWITCH WAS ON AT THE TIME. MY BROTHER'S HANDS WERE CLR (IN THE AIR) AT THE TIME. HE DID NOT ACTIVATE THE STARTER. I DID NOT EXPECT THE PLANE TO START AND WAS NOT TRYING TO PROP START IT. I WAS JUST TRYING TO RELIEVE THE PRESSURE FROM THE VAPOR LOCK. MY HANDS GOT INJURED DURING THE INCIDENT. I BELIEVE IT HAPPENED DURING THE KICK-BACK PRIOR TO THE ENG STARTING. EVEN THOUGH THE MASTER SWITCH WAS ON; I STILL BELIEVE THAT DUE TO THE VAPOR LOCK THAT I WOULD HAVE STILL BEEN INJURED WHEN IT KICKED BACK. I FOLLOWED THE PROCS I WAS TAUGHT YRS AGO IN CLRING VAPOR LOCK. I BELIEVE THAT MY INJURIES WERE CAUSED BY THE EXCESS PRESSURE IN THE VAPOR LOCK BECAUSE THE PROP GOT PULLED OUT OF MY HAND WHEN IT KICKED BACK. I BELIEVE WHAT CAUSED THE ACFT TO START WAS ALSO THE RELIEF OF THE VAPOR LOCK. THIS COULD HAVE BEEN PREVENTED BY HAVING THE MASTER SWITCH OFF; BUT I WAS NOT EXPECTING IT TO START. I WILL HAVE MY ACFT CHKED OUT BY THE A&P TO CHK FOR ANY GND ISSUES TO SEE IF THAT MAY HAVE BEEN PART OF THE CAUSE.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.