I am making up a hose to keep on my boat......two hoses that will splice in to one.....my primary reason for this is to not have to use the marinas greasy disgusting hoses in my boat....they always make a mess of my interior. My second reason is to be able to flush both engines at once.......that is where my question is......does a garden hose supply enough water for both engines together ? Will one engine pull all the water and the other be left dry ? Is this a bad idea, should I only make it one straight hose extension to keep on my boat and do one engine at a time ?

I have the exact same setup that you're describing. I bought a "Y" connector from Home Depot, and each end has a short length of hose connected. I connect one to each engine flush fitting and run them both at once. I've been doing this for years without any issues.

I guess it all depends on your main water supply though. My marina has city water and it comes out like a fire hose. But if you're on a well for instance and your flow rate is lower, then I suppose it's possible that you may have issues, but I'd say go for it.

Cool......City water and it flows very heavy....... I don't know why I didn't do this sooner....... Thanks Cig......

Just keep an eye on your water temps and feel the exhaust with your hands. If you do not have enough flow then one side of the exhaust will ussually get warm/hot. I know that at my vacation house I do not have enough water for that but at my home I probably do. Also make sure you use those thicker ID hoses so you can get the flow that is needed. If you use the cheap hoses then your will restrict the water to much.

Cool deal. This is what I bought. 11 bucks at Home Depot. Each end goes right into each flush fitting.

Good tips Audio.......thanks......

Got it already......Nice!!

Dont rev the engines while doing it or you will suck the hose flat! Been there doen that!
Anyway it can be done but i would just make your self a small gauge and check the psi of the water from the supply you will be useing......city water pressure can vary anywhere form 35psi all the way up as high as 80psi depending on how close/far you are from the pumping station and what time of day too. Pressure goes up at night due to less volume being used...

Thanks Wally........