It looks like you are pushing too hard making it smoke. I would
check the engine manual and see and check maximum sustained RPM.
If the boat is new to you, someone may have put on a propeller
that has too much pitch and it is working the engine hard.

Leanne
s/v Fundy

"Sebastian" wrote in message
om...
Our 1986 Catalina 27 with Universal 18 diesel tends to run hot
(although not immediately, takes many hours), has low RPMs
(always,
although it ranges between 1750 and 2000 at full throttle), and
always
give off some black smoke. Additionally, it appears that there
may be
a tiny bit of black oil leaking behind the transon of the boat,
but
not a lot. Finally, we get a maximum speed of 4 1/2 or 5 knots
in
still water, which seems to be too little...

I am quite new to diesels, so know very little. Can someone
recommend
some easy things to check/fix. I've heard black smoke means
injectors,
but could that also cause the low RPMs?

Thanks!