I have 500 efi's with sea strainers and a hose hook-up in the engine compartment for flushing the engines. The bravos have low water pick ups. With the garden hose hooked up the sea strainer fills up with water and water starts to flow out of the exhaust. As soon as the engine starts the sea strainer empties immediately and it is very hard to see any water flowing. I'm worried about the impellors tearing or something worse failing.

Is the water flow from a garden hose enough to safely run the motor?

People have been running them on the garden hose for decades with no problems, myself included....so I'd say yes.

As long as its not sucking the garden hose flat, its ok.

You may have to get some hose pliers and restrict the flow coming out of the motor if you don't have enough water supply. Just start the motors and let them idle don't rev at all.

Funny my guy here has me hook 2 3/4" hoses up that feed both strainers.
Strainers have a balance tube on them. So I have two hoses running feeding the strainers and run one motor.

I just tried this setup Sunday and when I turn both hoses on and start the motor (500efi) the strainers do not empty.

Granted he also likes to see a bunch of water volume to rinse the salt water out.

Is there any steam coming out your exhaust?

Typical garden hose will give you about 5 gallons per minute or so.......depending on your local pressure....its plenty at idle....but start revving it for longer periods of time and it will cause issues.. Oh and don't duck-tape the hose into the feed line going into the strainer like i did once!! The seawater pump will collapse the hose! LOL

My motor is hooked up to 50 gal tank, w/garden hose full on it can keep up with engine (1) at idle, if I rev it 2,500 rpm it empties tank in no time FLAT (hose full blast in tank).

Yep, just don't rev it much.

I haven't run them longer than a minute max. So the motor never even got warm.

Thanks for all of the fast replies.