Dry rack storage with lighting headers?
 

I'm having my boat rack stored this season. I previously was letting the water out of my lighting headers after I was done and had it out of the water on the trailer. Now that I just leave the boat in the staging lane I can't release the valve on the headers because the water doesnt stop flowing since the boats in the water. The headers aren't Stainless Steel on the inside. What can I do to correct this?

convert to Full Closed cooling ....

Closed cooling doesnt include the headers.

A "full" closed system would ....... 1/2 system is just the motor .....raw water flows thru the Heat exchanger then thru the exhaust .....
A Full system the raw water flows thru the heat exchanger and the out thru the hull ..... The closed side flows thru the motor and the Exhaust .....your righ though the 1/2 system is most common ......m

Install a valve in your intake hose to close off the sea water coming in. Close valve and drain headers.

REMEMBER TO OPEN the VALVE next time you put boat in the water.

I keep my boat @ an indoor dry rac storage yard. All we have is salt water here. What guys that care enough do, is to wait a while for the fork truck operator to haul you out, and simply flush your engine on the fork truck. After a while, the workers get to know you and give you priority over a boat that doesnt get flushed out.
I have a really cool set up I would like to tell about. I have full dry CMI's and 1/2 closed cooling ( just the engine ). My headers have water dumps on the end of the tails. All I need to do ( on the fork truck ) is push the hose up against the water dump ( one side @ a time ) and squirt water into the dump. Fresh water goes into that header, through my heat exchanger, oil coolers, hoses and out the other header dump. All my raw water side gets flushed in 1 easy step without even running the engine!

Good idea ..... do you use Saltaway or simular product?

No, just alot of water. I am not a big believer in salt away. This past winter I tore down a pair of 575 SC's that were flushed with salt away often. NOt every time, but oftem enough. Upon tearing them down, the intakes were so rotted by the water crossover, they had to be replaced. They were just about rotted through to the lifter valley. Maybe with out saltaway, they would have gon through?? Dont know for sure.