..I had an MD7B on my first boat
, which I later swapped out for a 2003 series.
In the process I also removed the old fuel tank
and on a whim opened the inspection
hatches on top of the tank allowing me a view inside.
Was I ever amazed. The bottom and sides of the tank was covered in a dark colored heavy disgusting-looking slime. It was a good thing, my main fuel pick up line was 1.5" (37 mm) or so off the bottom of the tank, as I would have been sucking this stuff up all day long.
The MD7 series engine
is no longer made, mine was installed 'round about 1980 or so, so if your boat
has this engine, it is highly likely that it ( and the tank" was likely installed 40 some years ago.
My suggestion would be, even though the engine is running fine now, to have the fuel and tank cleaned. Testing the engine, while the boat is in a slip does not replicate the movement of the boat at sea, when you ( and the tank) will likely be bouncing around, stirring up all sorts of goop in the tank.
It doesn't help to have clean filters if the main intake line gets clogged up from tank residue.
While I'm at it. The MD7 series engines were raw water
cooled. This would be a good time to remove the cylinder head
, inspect and ream out the water cooling