C152 PLT LOST ENG PWR AND HAD A ROUGH RUNNING ENG DUE TO UNRECOGNIZED CARB ICING.

Narrative

WHILE FLYING XCOUNTRY FROM CRQ TO DVT OVER BORREGO SPRINGS; CA; MY RPM'S BEGAN TO FLUCTUATE AND THE ENG CUT IN AND OUT IN A PROGRESSIVE MANNER. JUST PRIOR TO THIS I HAD INITIATED A CLB FROM 7500 FT MSL TO 9500 FT MSL AND HAD JUST LEVELED OFF. AT THIS TIME I WAS GETTING FLT FOLLOWING FROM ATC AND HAD ADVISED THEM OF THE PROB AND ADVISED THAT I WOULD BE DSNDING BACK TO 7500 FT MSL AND TURNING AROUND TO RETURN TO CRQ. I DID NOT REALIZE AT THIS TIME THAT I HAD CARB ICING. I THOUGHT THERE MIGHT BE A PROB WITH THE CARB OR ENG CAUSED BY THE INCREASE IN ALT AND HOPED BY DSNDING BACK TO 7500 FT THE SIT WOULD CORRECT ITSELF. AT 7500 FT MSL THE PROB PERSISTED AND AT THAT TIME I DECIDED TO LAND AT L08. AS I WENT THROUGH MY DSCNT CHKLIST; I REALIZED THAT THE PROB WAS PROBABLY CARB ICING AND APPLIED CARB HEAT. AS I CONTINUED TO DSND THE PROB WENT AWAY. AFTER LNDG; I CONDUCTED A RUNUP AND CHKED THE MAGNETOS AND EVERYTHING CHKED OUT FINE. THIS BEING THE FIRST EXPERIENCE I HAD WITH CARB ICING; I CALLED MY FLT SCHOOL AND SPOKE WITH AN INSTRUCTOR AND WE AGREED THIS WAS A CASE OF CARB ICING. I THEN CONDUCTED ANOTHER PREFLT AND RUNUP AND EVERYTHING CHKED OUT. I CONTINUED ON WITH MY FLT WITHOUT INCIDENT. BEING IN VMC AND OVER THE DESERT; THE LAST THING I THOUGHT OF WAS CARB ICING. ALSO; WHEN THE SIT BEGAN; I WAS INDECISIVE ABOUT LNDG RIGHT AWAY OR RETURNING TO CRQ. I REALIZE NOW THE BEST THING; IF POSSIBLE; IS TO LAND AS SOON AS PRACTICAL AND CHK EVERYTHING OUT ON THE GND.