this is what i found i missed one # in the motor bracket should be 3117803 may be missing one number at the beginning but i can't read it as it is worn away
That didn't work either. Look for a round plug with numbers on it. On my 150 it was on top of the motor. If you find some more numbers go the Mercurypartsexpress and put the number in. If it doesn't take it you know is no good and probably a part number. If you find a good one you can go to Maxrules.com and find the year. Good luck.