Last sunday after an afternoon of sailing in good weather, I turned on
the engine to return to the dock, becasue I was a little distance I
gunned the engine up to 3000 rpm almost thh max, and notices a huge
plume of black smoke coming from the exhaust in the back, when I
looked over to see if water was emerging from the exhaust I saw that
oil was being “spit” from the exhaust. I turned off the engine and
continued to port under sail. When I was close by and the wind was
agaisnt me and in close quarters for docking I started the engine
again, it ran for abut 10 minutes at slow speed, and everything looked
normal, water emerged, no black smoke no oil being ejected from the
exhaust. Later at dock I opend the engine cover and looked at the
engine to see if there was any signs of oil – nothing everything was
clean. Any thougths? should I be worried?
When did you change your air filter last time? New filter is probably
due.
It is quite typical to see black smoke when you accelerate engine all
way up. Back smoke means that some fuel isn’t burning completely. Oil
you saw most likely wasn’t engine oil, it was a fuel.
Anyway, it is normal behavior for older diesel engines.
I have experienced the same issues: 1. Cleaned out the fuel tank , found water at the bottom of tank, brownish in color. 2. Cleaned the barnicles off the prop. 3. Replaced the exhaust elbow I found the exhaust elbow to be the true cause of the black smoke at 3000 rpms. F 36/38From: “odl_nyc” <odl_nyc@…>Date: Thu, 25 Sep 2008 23:54:34 -0000To: <FreedomOwnersGroup@yahoogroups.com>Subject: [FreedomOwnersGroup] Oil in the Exhaust Last sunday after an afternoon of sailing in good weather, I turned on the engine to return to the dock, becasue I was a little distance I gunned the engine up to 3000 rpm almost thh max, and notices a huge plume of black smoke coming from the exhaust in the back, when I looked over to see if water was emerging from the exhaust I saw that oil was being “spit” from the exhaust. I turned off the engine and continued to port under sail. When I was close by and the wind was agaisnt me and in close quarters for docking I started the engine again, it ran for abut 10 minutes at slow speed, and everything looked normal, water emerged, no black smoke no oil being ejected from the exhaust. Later at dock I opend the engine cover and looked at the engine to see if there was any signs of oil – nothing everything was clean. Any thougths? should I be worried? Freedom 36
When did you change your air filter last time? New filter is probably
due.
It is quite typical to see black smoke when you accelerate engine all
way up. Back smoke means that some fuel isn’t burning completely. Oil
you saw most likely wasn’t engine oil, it was a fuel.
Anyway, it is normal behavior for older diesel engines.
I’m curious: what did the exhaust elbow do to produce black smoke? Was
it clogged? Leaking? I made my own exhaust elbow but am not sure if it
functions okay.
Thanks,
Michel
Cleaned out the fuel tank , found water at the bottom of tank,
brownish in color.
Cleaned the barnicles off the prop.
Replaced the exhaust elbow
I found the exhaust elbow to be the true cause of the black smoke
at 3000 rpms.
F 36/38
-----Original Message-----
From: “odl_nyc” <odl_nyc@…>
Last sunday after an afternoon of sailing in good weather, I turned on
the engine to return to the dock, becasue I was a little distance I
gunned the engine up to 3000 rpm almost thh max, and notices a huge
plume of black smoke coming from the exhaust in the back, when I
looked over to see if water was emerging from the exhaust I saw that
oil was being “spit” from the exhaust. I turned off the engine and
continued to port under sail. When I was close by and the wind was
agaisnt me and in close quarters for docking I started the engine
again, it ran for abut 10 minutes at slow speed, and everything looked
normal, water emerged, no black smoke no oil being ejected from the
exhaust. Later at dock I opend the engine cover and looked at the
engine to see if there was any signs of oil – nothing everything was
clean. Any thougths? should I be worried?
Normally a restricted exhaust elbow also causes an overheat situation
if the raw water injector is blocked and restricting water flow or if
the exhaust outlet itself is blocked it restricts the air/exhaust flow
through the engine and you are not able to make the RPM’s you need.
The injection systems governer will try and compensate for this by
increasing fuelling to provide more RPM’s (power) and as the air flow
is not there to burn the additional fuel you end up with black smoke
(vapourized unburned diesel) and in severe cases what looks like a
sheen of oil on the water which is diesel that is deposited into the
raw water and ejected through the exhaust.
As you can make 3,000 rpm and maintain it, I am not sure the elbow is
your problem, although it is worth checking as the Yanmar exhaust elbow
is notorious for getting clogged.
Have you actually run your engine at these RPM’s before? Have you
actually tried to run the engine at maximum designed RPM’s? If so and
have not managed to meet the manufacturers stated maximum, then you are
over propped and what you are seeing is a classic case of an over
loaded engine, this also results in overfuelling.
Bottom fouling or a prop covered in barnacles is a good possibility,
aparently barnacles have been a greater problem this year than previous
years. A quick dive over the side will determine this and at the same
time make sure there is nothing restricting the shaft turning, it is
not uncommom the pick up old line from crab pots or fishing nets.
Polypropolene line can get trapped between the propeller and cutless
bearing and actually melt into a mass that can ‘bind’ the shaft but not
stop it rotating. Check you can turn the shaft freely by hand when the
engine in stopped and out of gear. These reult in overfuelling.
Another possibility is old fuel, not a water issue, but just old fuel.
I have this problem in my F32H that was used as a cocktail platform for
a couple of years before I bought it recently. My fuel had a red tinge
to it and I assumed that ‘off-road’ diesel has been used in the tank.
Wrong, it turns out that even road diesel with a normal yellow/green
tinge can turn red over time. I am talking a year or two…
Finally, if all the above check out OK, you may be due an injector
replacement or rebuild. It is possible that the metering on the
injection system and off due to normal wear and the spray pattern from
the injectors is not uniform or the injector nozzles do not seal and
drip, this will cause incomplete combustion and result in unburned
fuel. Removing the injectors and getting a local diesel injector shop
check the spray pattern, normally this is not expensive.
Posted by Bob (rweeks6508@…>)
This is not unusual under heavy loads or very high rpm. Remember everything is matched (at least it suppose to be) prop, shaft, couple, etc. My prop is a three blade prop (15x9) and I have been told its a little large for my setup Yanmar 2GM20F and at 2800 rpm is spits oil also. At 2000 rpm I am doing 4.5 knots and at 2500 5.5-6 knots. I also been told by prop experts once I get the properly matched prop I will be able to run at cruising RPM which s/b 3200 rpm or better.Bob On Thu, Sep 25, 2008 at 8:15 PM, vladimir_ud wrote:— In FreedomOwnersGroup@ yahoogroups. com, “odl_nyc” <odl_nyc@… > wrote: >. Any thougths? should I be worried? > > Freedom 36 > When did you change your air filter last time? New filter is probably due. It is quite typical to see black smoke when you accelerate engine all way up. Back smoke means that some fuel isn’t burning completely. Oil you saw most likely wasn’t engine oil, it was a fuel. Anyway, it is normal behavior for older diesel engines. best Vladimir F28 Cat Ketch
Posted by Bob (rweeks6508@…>)
I have already replaced my exhaust elbow so that is not the cause of my issue still the prop.BobOn Thu, Sep 25, 2008 at 8:27 PM, amarsib@… wrote:I have experienced the same issues: 1. Cleaned out the fuel tank , found water at the bottom of tank, brownish in color. 2. Cleaned the barnicles off the prop. 3. Replaced the exhaust elbow I found the exhaust elbow to be the true cause of the black smoke at 3000 rpms. F 36/38 ___________________________________From : “odl_nyc” <odl_nyc@yahoo. com> Date : Thu, 25 Sep 2008 23:54:34 -0000 To : <FreedomOwnersGroup@ yahoogroups. com> Subject : [FreedomOwnersGroup ] Oil in the Exhaust Last sunday after an afternoon of sailing in good weather, I turned on the engine to return to the dock, becasue I was a little distance I gunned the engine up to 3000 rpm almost thh max, and notices a huge plume of black smoke coming from the exhaust in the back, when I looked over to see if water was emerging from the exhaust I saw that oil was being “spit” from the exhaust. I turned off the engine and continued to port under sail. When I was close by and the wind was agaisnt me and in close quarters for docking I started the engine again, it ran for abut 10 minutes at slow speed, and everything looked normal, water emerged, no black smoke no oil being ejected from the exhaust. Later at dock I opend the engine cover and looked at the engine to see if there was any signs of oil – nothing everything was clean. Any thougths? should I be worried? Freedom 36
My e elbow was 2/3 restricted.From: “michel.capel” <michel.capel@…>Date: Fri, 26 Sep 2008 07:43:40 -0000To: <FreedomOwnersGroup@yahoogroups.com>Subject: [FreedomOwnersGroup] Re: Oil in the Exhaust I’m curious: what did the exhaust elbow do to produce black smoke? Was it clogged? Leaking? I made my own exhaust elbow but am not sure if it functions okay. Thanks, Michel — In FreedomOwnersGroup@yahoogroups.com, amarsib@… wrote: > > I have experienced the same issues: > 1. Cleaned out the fuel tank , found water at the bottom of tank, brownish in color. > 2. Cleaned the barnicles off the prop. > 3. Replaced the exhaust elbow > I found the exhaust elbow to be the true cause of the black smoke at 3000 rpms. > F 36/38 > -----Original Message----- > From: “odl_nyc” <odl_nyc@…> > > Date: Thu, 25 Sep 2008 23:54:34 > To: <FreedomOwnersGroup@yahoogroups.com> > Subject: [FreedomOwnersGroup] Oil in the Exhaust > > > Last sunday after an afternoon of sailing in good weather, I turned on > the engine to return to the dock, becasue I was a little distance I > gunned the engine up to 3000 rpm almost thh max, and notices a huge > plume of black smoke coming from the exhaust in the back, when I > looked over to see if water was emerging from the exhaust I saw that > oil was being “spit” from the exhaust. I turned off the engine and > continued to port under sail. When I was close by and the wind was > agaisnt me and in close quarters for docking I started the engine > again, it ran for abut 10 minutes at slow speed, and everything looked > normal, water emerged, no black smoke no oil being ejected from the > exhaust. Later at dock I opend the engine cover and looked at the > engine to see if there was any signs of oil – nothing everything was > clean. Any thougths? should I be worried? > > Freedom 36 >
I’m curious: what did the exhaust elbow do to produce black smoke?
Was
it clogged? Leaking? I made my own exhaust elbow but am not sure if
it
functions okay.
Thanks,
Michel
Cleaned out the fuel tank , found water at the bottom of tank,
brownish in color.
Cleaned the barnicles off the prop.
Replaced the exhaust elbow
I found the exhaust elbow to be the true cause of the black smoke
at 3000 rpms.
F 36/38
-----Original Message-----
From: “odl_nyc” <odl_nyc@>
Last sunday after an afternoon of sailing in good weather, I
turned on
the engine to return to the dock, becasue I was a little distance
I
gunned the engine up to 3000 rpm almost thh max, and notices a
huge
plume of black smoke coming from the exhaust in the back, when I
looked over to see if water was emerging from the exhaust I saw
that
oil was being “spit” from the exhaust. I turned off the engine and
continued to port under sail. When I was close by and the wind
was
agaisnt me and in close quarters for docking I started the engine
again, it ran for abut 10 minutes at slow speed, and everything
looked
normal, water emerged, no black smoke no oil being ejected from
the
exhaust. Later at dock I opend the engine cover and looked at the
engine to see if there was any signs of oil – nothing everything
was
clean. Any thougths? should I be worried?
Yes indeed, exhaust restriction can cause an engine to run rich …
the reason being - the cylinder is not completely evacuated and
recharged with clean air … then a fuel load sized for a clean air
charge is injected … resulting in a too-rich mixture.
A diesel engine that runs rich is not just a waste of money for fuel
but will cause other problems as well … carbon deposits on valves,
fuel washing lube oil off the cylinder walls (not too big a deal on a
diesel) … coking of the entire exhauset system causing more
restirction, turbo issues, etc …
The opposite is also true, modern engines are built to such fine
tolerences that exhaust restriction is finely calibrated and too low
a restriction can cause an engine to run too lean and burn valves …
though this is usually more of an issue with a fuel-injected gas
engine … so if you put straight pipes on your Lexus, don’t forget
to reprogram the chip…