Re: Draining Fuel tank
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If you haven't already solved it, I have a solution that works for me. Your problem is the length of lift portion of the hose and the weight of the diesel in the hose in that lift portion.
You can decrease the weight of the diesel in the lift portion of the hose by adding air pockets. With the suction on, lift intermittently the suction end of the hose for a split second allowing some air to enter. Do this several times until you have flow on the down side of the hose.
I learned this when acquiring my PHD in Shade Tree Engineering 🌴🌴
I only have about 30 gallons of fuel in my tank and I want to drain it. My boat is on the hard ,so I placed a five foot length of 1/2" cpvc tube into the tank and attached a 25' length of 1/2"OD plastic hose , I drop that over the side hoping I could siphon the fuel out. I attached the hose to a shop vac , sealing the connection with tape and yet it did not produce enough suction to pull the fuel up out of the tank by more than two feet ,about to the height of the cockpit seat. I was surprised by that ,it is a big vac ,with a lot of suction. Does anyone have a suggestion on how or what to use to suck the fuel up and out of the tank.