Gemmies ??
Had one of them 6V53N I think in a 34 footer, me mate and I had as lads.
Never put a spanner on it.
Converting fuel to noise, yup and virgins to whatever they become afterwards.
That
garump sound followed by the clatter at idle that shattered the silence in the local mooring when firing up at first light in the morning was quite satisfying. Got every one else going too.
If that didn't get em going, the howling as we pushed out to sea for a days fishing did.
"Bluddy Hoons" could be heard echoing in our wake.
Funny that's what "I" say nowadays.