Yanmar Operating and Maintenance Tips
1.Exhaust elbow
The Yanmar manual and the check
list from the distributor, Boatswain Locker, of the 3GM engines recommend that
the mixing elbow be changed at 600 hours.
Only the elbow needs to be changed. It is on other parts and
needs to be removed from the engine and a vice used to separate it from the
parts either side of it. This requires the appropriate gasket at the engine.
You also should mark the exact position of the old elbow so you get the same
angle. I intend to change mine this winter as preventative maintenance.
2. Water pump, European version by Johnson.
I found that I had developed a slow water leak where the
shaft from the pulley enters the pump. I decided to purchase a new pump and
then repair/rebuild the old one. Thus I will have a spare that will make it far
quicker to replace if the impeller fails. By the way I also noticed that after
7 years the larger of the fan belts, the one going to the alternator, was
cracked so I replaced that at the same time and will purchase another spare.
Dick Walker
C-320 (687) WindWalker II Coronado, CA
Correction ...... I should have
clarified that the exhaust elbow should be inspected at 500 hours assuming it
is showing no signs of restriction such as lower RPM's,
soot or black smoke discharge, overheating, etc. Any of these symptoms
appearing before 500 hours call for immediate inspection and probable
replacement.
Pete Clancy
While at the Annapolis Boat Show today, I talked with the
Mack Boring rep
regarding the Yanmar
diesels. Here is what he said.
Warm-up in neutral at idle speed of
900-1000 rpm. We should be able to hit hull speed between 2700 and 3100
rpm and we should be able to reach 3500-3600 rpm's. But he acknowledged that
many of us have problems doing so due to, "screwing around with different
prop configurations". The engine is designed for continuous operation at
three-quarters of maximum rpm's (3600 x .75 = 2700). He also said that the
engine mounted tachometer will read about 150 rpm's less than actual.
When shutting down, put it in neutral, let it idle for 3-5
minutes, then shut down. If the engine has been run
for a long time at low speeds, after the 3-5 minute cool down period, rev it up
in neutral 2-3 times then shut it down.
Based on something I was told long ago, I make sure that
every time I take the boat out, I run at 3000 rpm's
for at least 10 minutes.
Allan S. Field
Sea Shadow - #808
I agree and will change my SOP. One has to balance logic
against all of the 'experts' out there--another testament to this list as it's
great to bounce these things off everyone and get a sanity check.
Jon
> Jeff/Jon,
> If you only put 50-100 hours on your engine per year
then you have at
least 40 years before you have to
worry about it. If however you are blessed
with year round access to the water but cursed by the
typical wind forecast of "....light
and variable, less than 10 knots...." which translates to 2,3 or 4 knots
at best and almost guaranteed to be on the nose you will put on may more hours.
>
> The typical 18 wheeler seems to get 1m miles or more
before the engine is torn down or replaced. I'm guessing that they are only
driving on the road for 2-3000 hours per year but they generally leave the
engine idling even when they are eating, sleeping, fueling, loading, being
weighted.... so they probably end up with 5-6000 hours per year. At a million
miles that means that they rebuild/replace after about 7 years or 42,000 hours.
Wouldn't it be great if we could get 42k hours out of your
little diesels!
> Now that our boats are made out of what Hershoft called "frozen snot" the boats last
forever, provided they are reasonably maintained and upgraded. Which means that
oats that are 30-40 years old are very serviceable and very popular and usually
are priced in the 20-30k range? Not fun when you have to spend 8-15k to
re-power, you will never get that money back!
> While I could be wrong I don't think I agree with it is
ok to rev the engine when it is cold, even when it is during warm weather. Our
engines are made with all sorts of alloy's which have
different temperature coefficients of expansion. The designers take these into
account when they design and manufacture the engines. This means that when the
engine is cold you do not have the right tolerance in the bearings, gears,
rings, valve stems, push rods.... This means then when our high
compression engines fire all this "slop" results in additional noise,
vibration and it would seem to me wear.
> When we start our engine we seem to go through two
transitions. The first is very quickly after starting, the low oil alarm goes
off and the really loud pinging becomes just loud pining. I assume this is most
of the parts, lifters, bearings, rings.... are getting
a dose of oil. The second transition is after 3 to 10 minutes and seems rather
abrupt. I assume the combustion chamber is now up to
temperature and the fuel is being burnt evenly, the engine just seems to settle
down and run smother and quieter. I think I'm going to continue to be gentle
(no throttle) with the engine at start but based on this discussion I am going
to rev the engine at the end of the day before it is put away for the last
time. What do people > recommend, let it run up to 4000 RPM and then pull
the kill or run it up to 4000 RPM then throttle back and kill it when it is
back to 900?
> Bruce
> Somerset 671 SoCal
>
> Jeff,
> I think you have the right perspective...The same
mechanic/trainer also said, anything you do to these engines may be a matter of
whether you rebuild it after 4000 hours or 10,000 hours-- at 50-100 hours a
year, either > way, it's a loooong time and a lot
of abuse.....
> Jon Vez
> >
> > Don't sweat the warmup/revving
thing. Most agree you shouldn't load it until it's warmed up, but reving a diesel after starting it in the summer is simply a
non-issue. In the middle of winter is a different story because the oil doesn't
flow well.
> >
> > Revving a *Gas* engine that hasn't warmed up for a
couple minutes in cool or cold weather is a different story. Gasoline washes
the oil off the cylinder walls, while diesel doesn't really suffer from that
phenomenon given that Diesel fuel *is* oil.
> >
> > Clean oil, clean air, and clean fuel, running it
hard/fast it'll outlive many of us.
> > -JeffH
> >
> > I am certainly not an expert on this, but the
info. I received was from a two day diesel class I took that was put on by Mack
Boring....I guess I'm back to being confused??
> > Jon Vez
> >
> > > Running a cold engine up to full RPM is
probably the worse thing you can do to any engine. The Yanmar
manual says that you should run the engine up to full throtle
prior to shutting down, when the exhaust is hot and all bearings are at their
design tolerance.
> > >
> > > John Van Vessem
> > > Sojourn 645
> > >
> > >
> > > I posted several questions related to the
exhaust elbow as I was interested in proactively replacing mine (my boat is in it's 8th season in salt water).
> > >
> > > My confusion was whether the elbow was custom
made by Catalina like the muffler, or whether I could get it from a Yanmar dealer--than answer is BOTH.
> Some hulls (with the Yanmar)
had a custom elbow made by Catalina...even though I
suspected this was the case on
mine, I couldn't confirm until I went to a local Yanmar
distributor myself. Even Catalina
couldn't answer this question....Thegood news is that
if you do have a custom elbow from Catalina, you can indeed replace with a
stock Yanmar elbow...The bad news is, you need to buy
3 pieces (for about $360 vs about $160 for just the
elbow). The Catalina elbow is a one piece elbow, whereas the stock parts have a
manifold, an adjusting screw connector and the elbow. Once you have replaced
with the stock parts, you will only have to replace the elbow (top part) going
forward....
> > > As for time, Mr. Douglas had suggested 5-8
seasons is a good time to replace. One suggestion on
keeping the buildup under control from Mack Boring is to start the engine at
full throttle and bring it back to idle as soon as the engine starts...This
will blow a lot of the build up out and presumably delay the inevitable...
Jon Vez
> > > > Koen - There
are 2 concerns with the exhaust elbow. The first is that it clogs over time and
will impact engine performance. The second is that it eventually gets pinhole
leaks. Both happened on my previous boat. Trust me when I say that you don't
even want to think about the mess you will have if the elbow gets a pinhole
leak. The engine compartment fills with black soot that never completely goes
away no matter how much you clean, clean, clean, and clean some more. I intend to replace my
elbow prophylactically over the winter at about 500 hours,
change the hose to the aqua lift muffler, add a hump hose at the muffler, and
pull the muffler, send it back to Catalina, and have a duplicate muffler made
to sit on a shelf until when I need it. Again, you don't even want to think
about the mess if these parts fail.
> > > >
> > > > Allan S. Field
> > > > Sea Shadow - #808
> > > > I seem to remember someone mentioning
that the exhaust elbows on C320's get
clogged
and are recommended to be replaced every so often. My local mechanic, who will
do the very first service on our boat soon (so we do not have experience either
with him or with the engine service in general), recommends we order the elbow
and gasket from Perkins (I believe tadiesel sells
them?) in advance to save time. Is this a good suggestion? We have purchased
the boat used 2 seasons ago, so I have no idea what the history of this part
is. Thanks for any suggestions,
Koen