The
main cause your marine engine dying when you place it in
the water is usually because you tried to tune your engine
out of the water.
Read
this "How do I set my needle valves on marine engines?
How many turns out should my needles be set at?"
Other
causes are the tank arrangement. As the boat it propelled
forward the pick up in the tank may be starved for fuel.
All the fuel goes the the rear or stern of the boat from
not only the forward force but also the the bow lifting
up.
Shopping
without emptying the tank is usually caused from a pin hole
in the fuel line inside the tank.
The
tear resistance of silicon tubing is very low and it's not
uncommon to develop a hole where the fuel line is assembled
over the edges of brass tubing. If the engine runs well
on the first half of tank and then quits, it's almost always
caused by a hole in the pick up line inside the tank.
When
the fuel level is higher than the hole in the pick up tube
in the tank the engine will draw fuel through the pick up
tube and the pin hole.
When
the fuel level drops below the pin hole the engine will
start to draw air. This results in the fuel mixture leaning
out and the engine dying.
A tell
tale sign of this are bubbles in the fuel line while the
engine is running with a low level of fuel in the tank.
See
also cause of erratic
running
