WE ARE PARTING A RUNNING 1977 MERCURY 9.8 MOTOR THAT RAN BUT THE CDI WIRES WHERE JUNK AND WOULD CUT OUT ALOT, WE WHERE ONLY ABLE TO RUN ABOUT 10-15 SECONDS AND THE VIBRATION WOULD MOVE THE WIRES AND IT WOULD DIE. SERIAL NUMBER 5122473. MOST ALL PARTS WILL FIT THE 7.5HP AS WELL. POWERHEAD RAN FINE AND QUIET. WE FORGOT TO CHECK COMPRESSION LAST YEAR AFTER RUNNING BUT I CHECKED IT TODAY ON THE BENCH AND BOTH WHERE RIGHT ABOUT 90 PSI, THIS IS NOT A LOW HOUR POWERHEAD , I WOULD GUESS AVERAGE USE TO BE HONEST. ANY EXTRA SHIPPING WILL BE REFUNDED.