Pump Isolation Valves

[TeenGee]

I just finished installing a pair of isolation valves between the pumps and where the fresh water flush connects to the cooling lines.
The main reason I did this was so I could flush both engines at the same time. The hose I use to flush the engines did not have enough flow to flush both engines because of the amount of water that just runs out of the pump. When closed these valves eliminate the reverse flow out the pump. After flushing, opening the valves allows the engines to drain back through the pump.
A second benefit is the ability to flush the engines while still in the water. Third, in the event of an engine failure I can close the valve for that engine and not have to worry about hydro-locking the engine.
I used 1/2" FPT PVC ball valves and attached 1/2" barb fittings. I extended the valve handles with 1/2" PVC pipe and made a handle for the top of the pipe. The valves are open when the handle is pointing forward.
I am not concerned about forgetting to open the valves before operating the boat. If I don't notice the lack of pisser flow, the engine overheat alarm will sound and I will open the valves.

 

[yam240sx]

did you use plastic barb fittings or brass

 

[TeenGee]

All plastic fittings and stainless steel hose clamps.

 

[yam240sx]

nice .. I like the extension levers you added .. how long have they been on ? and notice any impeding on flow ?

 

[TeenGee]

I installed them in late October.
No problems. 1 trip to the keys and 180 mile trip over New Year.
I like the ability to flush the engines while still in the water.

 

[yam240sx]

i think i may go your route (pvc) .. So flow out the pissers is same as factory flow ...? no overheat alarms ect ?

 

[TeenGee]

Plenty of flow out all 6 pissers.
I think thrust from the pissers adds 5 MPH to the top speed.