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.