[steplift20]

my 150 1988 mercury runs great except sometimes when im running inreverse you her a thump or low bang from the engine its been doing this for about 3 years so when im backing up i take it slow cause then it dont do it dont know what it could be
changed my lower unit oil and no metal in ther i was thinking if it could be something with the trim since going in reverse it would be trying to pull the motor up just a thought