T&T: Ask the question a different way. was: Running higher HP engines at low speeds.

[Dave Cooper]

Marin wrote: I will be surprised if anyone posts that their engine failed--
quit---
due to slow running.  But it would be interesting to know if someone's
higher-performance engine has begun losing performance, became harder to
start, smoked more, etc. after hundreds-- or thousands--- of hours of
low speed running, or more significantly, low temperature running.

We might not see this in the ownership of a boat from new as most people
sell/trade before they get this kind of hours on it. However in our trawlers
which range from new models too many built in the 70's our engines do have
the hours that will show the effects of usage. Those with high HP ones
seldom get beyond 5000 hrs. Those with HP matched to the usage can get
10-20000 hours if properly maintained.

To the other poster re the Perkins. In the charter business the natural
Perkins 4-236 engines routinely got 10-12000 hours out of them. Then pull
them and use them as moorings while you install a new one.,
Yanmar 4 cylinders, non turbo'd, were good for 7500 hours and the 3
cylinders were good for 5000. Many of these hours were put on running at the
dock with just the load of the fridge compressor and alternator. The oil
pressure would be good but they all suffered for hard starting and the blue
smoke of death towards the end from running at the dock with just the load
of a fridge compressor and the alternator on them.

The few boats that had turbos would halve the hours before they needed
replacement. BTW, it is far cheaper to replace an engine that to rebuild one
in this business. Old one out and new one in a few hours and back out on
charter. If you buy a dozen engines at a time the price is a bit better too
;-)

We have less experience with the larger Yanmars of 2-450 HP but they
certainly don't have the life of the smaller ones. This could be do to usage
patterns or the stress in trying to get a lot of HP from a small light
block.

The Cats in some of the "fast trawlers" are not doing well as compared to
the hours they should be getting, IMHO. They require very high maintenance
levels. They are seldom run at operating temps as the price of diesel is now
$4.50 or so per gallon. Over the last couple of years the blue smoke level
is going up dramatically. I think this indicates a faster rate of glazing,
etc that occurred when fuel was $2/gal and the charter guests didn't wince
at a $1000-$1500 fuel bill

This is just my experience/observations over thousands of these engines in
daily use throughout the Caribbean over a couple of decades.....probably not
worth much I suspect ;-)

Dave & Nancy
Swan Song
Roughwater 58