On Mon, 08 Mar 2004 15:37:41 +0000, Sebastian wrote:

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!

I'm QUITE familiar with Universal diesels, having messed with one for 15 years
before replacing it myself. As others have said, sounds very much like too much
prop. Try full-throttle at idle: what does the tach say? Also, you should
calibrate the tach if you're going to be doing any tests - a "hand tach" is a
valuable investment for a wonky diesel.

That engine should reach 3000 rpm full-throttle in neutral ("high idle"). It
should also reach close to 3000 (say at least 2700-2800) at full throttle under
load ("WOT"). I'd guess it should have about a 14x7 prop (14" dia, 7" pitch),
at most. It should be stamped on the prop (usually 14x7x1RH)

Other things to check: How easy is it to turn the shaft manually when in
neutral? Does the shaft turn while under sail? If not, maybe it's jamming,
causing too much load.

Then again, there could be a problem with the engine. Is it hard to start? Is
there smoke when running in neutral? It's a pretty simple engine: have the
injectors and high-pressure pump checked, then compression. Hope it's the
injectors - the other problems are major $$.

Yes, with the proper prop you should get hull speed with that engine, cruising
at 5 or so at 2400rpm, hitting 6.5 WOT.

Lloyd Sumpter
"Far Cove" Catalina 36 - brand-new M25XPB