Maybe I said that wrong - but here is the gist - as I understand it ....
The cam of the fuel pump may stop with the lobe at the top - side - or
bottom of it's turn .
If at the top the diaphragm operated by the prime lever will have full
travel - and a complete filling of the fuel pump body - the pump will be
easy to use and will prime quite rapidly and the diaphragm will be at it's
most relaxed .
If on the side of the lobe the pump will have only half stroke and
priming may take a lot more strokes and the diaphragm will be in a half
stretched position .
If on the bottom of it's turn - the diaphragm may be at the end of
it's travel and the use of the lever to prime will be useless ( until the
engine is rotated slightly to allow some travel of the cam lever ) and the
diaphragm will be in a fully stretched position .
In these two last conditions the stretched membrane will open any
pinhole to a point where fuel may find it's way past - where it would not
do so in the relaxed position - sometimes the pinhole in the diaphragm
cannot be found on inspection and is assumed not to be there - but it is
even though you may not be able to find it ....
This may allow fuel to seep past the diaphram - especially if the tank
is full and exerting pressure in the line .. and depending on how your pump
is constructed drain either into the bilge or into the engine sump... it
is a syphon condition albiet it a very small one ..
It's always a good idea to turn off the fuel cock when leaving the boat
for any sustained period of time - but sometimes a pain to do so and I
forget ...
Without a rebuild kit - ya buy another whole pump if you can find one
... and diaphrams don't last forever ...
Is this conversation appropriate / inappropriate for Valentines
day - week ??
Ken
Mrs. Hudson
Maybe I said that wrong - but here is the gist - as I understand it ....
The cam of the fuel pump may stop with the lobe at the top - side - or
bottom of it's turn .
If at the top the diaphragm operated by the prime lever will have full
travel - and a complete filling of the fuel pump body - the pump will be
easy to use and will prime quite rapidly and the diaphragm will be at it's
most relaxed .
If on the side of the lobe the pump will have only half stroke and
priming may take a lot more strokes and the diaphragm will be in a half
stretched position .
If on the bottom of it's turn - the diaphragm may be at the end of
it's travel and the use of the lever to prime will be useless ( until the
engine is rotated slightly to allow some travel of the cam lever ) and the
diaphragm will be in a fully stretched position .
In these two last conditions the stretched membrane will open any
pinhole to a point where fuel may find it's way past - where it would not
do so in the relaxed position - sometimes the pinhole in the diaphragm
cannot be found on inspection and is assumed not to be there - but it is
even though you may not be able to find it ....
This may allow fuel to seep past the diaphram - especially if the tank
is full and exerting pressure in the line .. and depending on how your pump
is constructed drain either into the bilge or into the engine sump... it
is a syphon condition albiet it a very small one ..
It's always a good idea to turn off the fuel cock when leaving the boat
for any sustained period of time - but sometimes a pain to do so and I
forget ...
Without a rebuild kit - ya buy another whole pump if you can find one
... and diaphrams don't last forever ...
Is this conversation appropriate / inappropriate for Valentines
day - week ??
Ken
Mrs. Hudson
