On Fri, 01 Aug 2008 18:03:18 -0700, Stephen Trapani
wrote:

Thank you all for your opinions about my raw water cooled Yanmar.

If I just let it do what it's been doing for thirty years, eg, running
below 120, Is it bad to let it run at idle for long periods? I would
like to use it as a generator sometimes while I'm using my 1500w
inverter or just to charge the batteries. I had previously been under
the impression that it was a bad idea to run it for very long without
engaging the prop because the motor runs so cool, so I tried not to do
that much.

After observing the temperature gauges (installed and manual) it seems
that running it engaged doesn't really warm it up much! Crazy.

So, bad to run it at idle much?

Stephen

You are going to get a thousand reply saying "Horrors! Don't ever let
your engine run at idle!!!!!! It's terrible; Terrible!"

If you want to be scientific it is likely that running a diesel engine
for long periods at very low RPM, and probable resulting low block
temperatures, is undoubtedly not the ideal practice but in real life I
notice that welding machines, trucks, heavy equipment, dry land
generator sets, drilling rigs, and just about every other diesel
engine in creation are run at idle for long periods with no noticeable
problems.

Probably, if you are running your propulsion engine to charge
batteries you aren't running it at idle anyway. For my old Perkins
4-107 to generate a respectable amount of amps it needs to be turning
about 1500 RPM.

Years ago I was up in Oklahoma looking at an oil field. A mile square
and wells about 100 yards apart and pumping jacks on every one of
those wells powered by one single cylinder diesel engine running on
crude oil that drove the pumps by pull rods running all over the
field.

I asked the Motorman how long the old engine had been running and he
told me that it was running when he was hired 15 years ago and had
never quit. The old engine had sat there for God only knows how many
years thundering along at 500 RPM. 20 years @ 24 hour/day = 175,200
hours........




Bruce-in-Bangkok
(correct Address is bpaige125atgmaildotcom)