Rod McInnis wrote:

:If you do this often there is a real easy modification you can make that
:will make this job a LOT easier.
:
:Cut the hose from the seacock in some easy to get to place, the closer to
:the water pump the better. Install a Tee in the hose. Install a valve on
:the third leg of the Tee. Install a female hose fitting on the open side of
:the valve.
:
:For normal operation the valve is closed and the raw water pump draws water
:from the lake just like always.
:
:For trailer operation, you open the valve and attach the water hose. When
:you turn the hose on, the water flows out the hose then out the seacock on
:the bottom of the boat (do NOT close the seacock!). When you start the
:motor, it will draw the water up from the Tee.
:
:Just be sure to close the valve when you are done with the hose.

I've thought about installing this setup on my boat (130hp Volvo I/O),
but I was concerned that, when using the garden hose for water, the
water would not be sucked up by the engine mounted raw water pump and
instead just go out the hose that normally carries water from the
outdrive's water intakes to the water pump. Am I wrong about this?

Now what I do is attach the garden hose to a 4' length of clear hose
that has female garden hose fitting on one end and nothing on the
other. I then remove the hose from the intake side of the water pump
and replace it with the naked end of the clear hose that is attached to
the garden hose. Before I attach it though, I turn the water on at the
main garden hose valve and make a mental note of how far I need to turn
the handle in order to get a fairly low pressure stream of water coming
out the end of the hose I'll be attaching to the water pump. It sounds
complicated, but it's actually very simple!