86 Volvo Penta 350 white smoke
fzbuilder
is no smoke, but when it gets warmed up around 170, it starts putting
out white smoke. My oil is clean and the engine runs pretty smooth
however I am getting very little to no water out the exhaust and yes I
have the outdrive with the prop off resting in a tank of water. No
leaking water into the bilge. I just replaced the impeller and am now
thinking of the water pump, but the smoke is making think there is
another problem. Any help would be appreciated. Thanks
Bruce In Bangkok
Usually white smoke in the exhaust is caused by water leaking into the
combustion chamber.
Cheers,
Bruce
(bruceinbangkokatgmaildotcom)
Witek
"White smoke is water vapour. Lots of white smoke is lots of water
vapour!
When a car is first started on a cold, damp day you see white vapour
coming from the exhaust. This is water vapour condensing in the
exhaust, because for each
gallon of petrol or diesel fuel burned, you get a gallon of water as a
product of combustion.
On a boat with a water-cooled exhaust, the cooling water being
injected into the exhaust system masks this relatively small amount of
water vapour. Some people expect a cylinder-head gasket leak to show
up as water vapour in the exhaust, but the quantity
of water would be just too small to be seen on a boat.
Normally, a small engine would not have visible water vapour in the
exhaust. A powerful engine being run at high speed, such as on a
planing motor cruiser, would have a fair amount of water vapour
visible in the exhaust, and this is quite normal.
Some books describe the smoke from fuel injection problems as being
‘white’. To me this is actually ‘light grey’, but the difference is
small. Watch a diesel, especially a big one, being started from cold
and you will see quite a lot of varying colour smoke.
The lightest of this is ‘light grey’. You would not expect ‘white’
water vapour when starting from cold.
Noting this should help to distinguish between the two.
Blue smoke comes in a number of different shades and hues. It ranges
from a light hazy almost white colour through to dark blue. Watching a
big diesel start shows a mixture of all possible hues!
Blue smoke is often an indication of burning lubrication oil in a worn
engine, but fuel can give blue smoke as well. Blue smoke results
because some of the fuel droplets (or lubricating oil) do not burn at
all. This is because if a fuel droplet is too large in diameter it
will not burn (this is a function of its surface area and mass). The
size of the unburned droplet determines
the shade of blue.
The fuel injected by a serviceable injector has droplets of the
correct size to burn properly. When the engine is cold, some of this
fuel may condense on cold surfaces of the combustion chamber and
cylinder and form larger droplets that will not then burn.
As the engine warms up, these condensed droplets will become smaller
and, at some stage, will become small enough to burn. An engine
running at light load may have some fuel condensation producing some
droplets too large to burn, giving visible smoke.
A worn injector may produce a deformed spray, producing some fuel
droplets too large to burn.
A fuel injection pump with incorrect timing may supply some of the
fuel to the injector too early or too late. Fuel supplied at the wrong
time may reach the cylinder when the temperature is too low for
combustion (too early) or there is too little oxygen left (too late).
This fuel will be unburned and will result in blue smoke."
Witek
-------------------------------------------
http://chomikuj.pl/Sailing
Witek
Engines" by Paul Dempsey:
Whitish or blue smoke at high speed and light load, especially
retarded.
when engine is cold. As temperature rises, smoke color changes to
black. Power loss across
the rpm band, especially at full throttle.
Injector pump timing - Set timing.
--------------------------------------------------------------------------------------------------------------------
Whitish or blue smoke under light load after engine reaches operating
temperature. Knocking may be present.
Leaking injector(s). Repair/replace injector(s).
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Light blue or whitish smoke at high speed under light load. Pungent
odor.
Over-cooling. Replace thermostat.
--------------------------------------------------------------------------------------------------------------------
Blue smoke under acceleration after prolonged period at idle. Smoke
may disappear under steady throttle.
Leaking valve seals. Replace seals, check valve guides/stems.
Witek
-------------------------------------------
http://chomikuj.pl/Sailing
brian whatcott
...from a blown cylinder head gasket. This can be reasonably easy to
fix, if caught quickly, before the mating surfaces erode too much.
Brian W
Richard Casady
Only problems with that idea is that first of all, water doesn't do
that. Each pound of fuel burned produced abot a pound of water. Then
there is the water dumped into the exhaust elbow. Lots of piston
airplanes have used water injected into the intake manifolds to
prevent detonation. Jets have used water injection to increase the
mass flow, hence thrust. No smoke in either case. You can get wisps of
cloud that evaporate almost instantly and never make it more than a
foot from the transom, but it isn't smoke anymore than the wisps of
white at the tailpipe of any engine in the winter are smoke.
Glycol will indeed cause white exhaust smoke. My Starcraft is glycol
cooled. It had a blown head gasket when I got it. Luckily it has a
inline four, something you can work on. I will ask the previous owner
about glycol smoke.
In short, never with water, with glycol always.
Casady
Bruce In Bangkok
Close but no cigar.
Jets use water injection to augment thrust however the EGT is high
enough that the water vapor is not visible.
Internal combustion engines use water injection to allow increased
power settings but again, the water quantity and exhaust gas
temperatures are sufficiently high that the water vapor cannot be
seen.
However I'm not going to argue with you. Google on white smoke in
exhaust and you'll find some 145,000 others who will tell you that
water in the combustion chamber causes white smoke - argue with them.