diesel back pressure
 

i have read of the importance of insuring that
manufactures specs on back pressure are not
exceeded, but i can find no numbers for my
yanmar 2gm15. does 48" from bottom of water
lift to top of transom gooseneck using 1.5" hose
sound excessive?
john

diesel back pressure
 

That really applies when the diesel is turbo charged and run under heavy
loads for long periods of time . Back pressure is what keeps the exhaust
valves from burning .Your situation poses no problem.I am diesel mech. for
Mercedes.

Sal


"John Knox" wrote in message
...

i have read of the importance of insuring that
manufactures specs on back pressure are not
exceeded, but i can find no numbers for my
yanmar 2gm15. does 48" from bottom of water
lift to top of transom gooseneck using 1.5" hose
sound excessive?
john

diesel back pressure
 

John Knox wrote:
i have read of the importance of insuring that
manufactures specs on back pressure are not
exceeded, but i can find no numbers for my
yanmar 2gm15. does 48" from bottom of water
lift to top of transom gooseneck using 1.5" hose
sound excessive?
john


I don't know. How far down does the outlet drop from the top of the
transom gooseneck?

My 1/2/3 GM installation manual quotes 27 inches of water maximum
exhaust backpressure. This is _not_ the same as the vertical lift.
It can be measured by tapping into the exhaust elbow and comparing to
ambient pressure.

Evan Gatehouse

diesel back pressure
 

Evan Gatehouse2 wrote:
: John Knox wrote:
: i have read of the importance of insuring that
: manufactures specs on back pressure are not
: exceeded, but i can find no numbers for my
: yanmar 2gm15. does 48" from bottom of water
: lift to top of transom gooseneck using 1.5" hose
: sound excessive?
: john
:

: I don't know. How far down does the outlet drop from the top of the
: transom gooseneck?

: My 1/2/3 GM installation manual quotes 27 inches of water maximum
: exhaust backpressure. This is _not_ the same as the vertical lift.
: It can be measured by tapping into the exhaust elbow and comparing to
: ambient pressure.

: Evan Gatehouse

i don't think that the drop will have any effect on the back pressure -
i am thinking of installing a vetus transom gooseneck which is an enlarged
chamber with an inlet at the top an an outlet at the bottom - the back
pressure is going to develop from the waterlift to the maximum rise
with no reduction due to the fall in the outlet.

diesel back pressure
 

Because the vertical column will not be full of water, it is an engine and
there is a lot of exhaust gas, the vert. rise is not the same as the
backpressure. Measuring the backpressure will be prone to error because you
need to measure static pressure without getting any dynamic pressure. I
owned a boat with the 3GM30 engine. Exhaust hose was 1.5 inches and the
rise was at least 48 inches. No problem with engine was ever noted. Of
course the waterlift muffler has to be large enough to accommodate the water
that will flow back after engine shutdown.
Dave
"John Knox" wrote in message
...

i have read of the importance of insuring that
manufactures specs on back pressure are not
exceeded, but i can find no numbers for my
yanmar 2gm15. does 48" from bottom of water
lift to top of transom gooseneck using 1.5" hose
sound excessive?
john