CcanDo

What would be wrong with installing a fuel shut off valve close to the fuel tank pickup tube ?

Control of the valve could simply utilize a ball valve handle or a Morse cable for cockpit control.( Recip. aircraft use a morse cable for mixture control/idle shut down.)

Present fuel quality is thought to deteriate over some period of time. "Old fuel may produce varnish, low octane and fuel system problems".

Therefore, one could close a valve with the engine ONLY AT IDLE and effectively run the fuel system dry. Further,the valve would be used when changing fuel filters. Subject to accessability and control, the valve may be utilized as part of an emergency procedure during an emminent catastrophe.

The valve, plus a seperate electric fuel pump could be configured to pump the fuel tanks dry or to the bottom of the pickup tube.

I'm not aware of any OEM boats with a fuel tank shut off valve.....Is there a reason ?

Wally

iTrader: (1)

hmmm thats strange......my 1984 scarab had tank shut off valves...my 1986 stinger has one....ive seen plenty of other boat with them....come to think of it...i dont think ive seen one without a shut off valve...could it be that yours may have been modified at some point and someone took it off?

CcanDo

Wally, Guess I've been running in the wrong circles.

Do you use the valves ? If yes, would you please elaborate.

Thanks !

Deltarat

I have my Fountain set up with a shut off valve for both the fuel and water. The fuel shut off is right out side of the tank in the bilge area. The water shut off I installed right where the pick up enters the boat. I wanted to make sure that if I ever had a water problem I could shut off the inflo of water to the baot and repair it ie open sea strainer ect. with out sinking the boat. I have also thought alot about adding a t fitting to the supply line feeding the sea strainer and putting a valve there as well. Then if I ever experienced a catastrophic situation where my bildge pump could no keep up with the water inflo I could simpley shut in pick up off and open the t valve and use my motor to pump water out as needed until I could get to safety.

Wally

iTrader: (1)

Only times i have ever used my shut off vales was when pulling motors and dissconnecting the fuel system....or when i ran the engines dry for winter storage....other than that i realy didnt see a use for them honestly...maybe as a theft deterent for joy riders....wouldnt get very far when they ran out of gas

baronbob

No reason why you could not use a valve to starve your fuel system but I am not sure you would be accomplishing what you want. If you have a carbureted motor you would run the bowl dry and in turn the inside of the carb. the filter would be full. If you have an efi set-up I am not sure the system would be completely dry. I have been running boats in the cold West for years and aside from fogging the cylinders I have never bothered with draining EFI or carbs. By the way the airplane cut-off is to protect against a hot mag. and someone moving the prop. Lots of boats have cut-off valves.

CcanDo

Today's fuel seems to deteriate over a short period of time. Small engine dealers refer to the lawn mower as having throw away motors. They blame fuel as part of the short life expectancy. In the past, I don't recall varnish forming as quickly as it does now.

My boat engines are both injected and carbuerated. You make a good point regarding the filter. Perhaps one should remove and drain the filter, partially refill w/Marvel Mystery oil and re-install.

I have over 6,000 hrs. in various recip. aircraft plus turbine time and all the tickets except ATP. My shutdown procedure has always been:throttles at idle, props full pitch, idle shut off closed, fuel valves to off ,mags off, master off and any electronics off. Paper work,charts and plates are then stored and then deplane. Technically, I agree that the idle shut off is to HELP prevent an engine from firing because of a hot mag,subject to leaning on the prop. However, I don't want boiling fuel in the system, preventable by using my shut down procedure.

Pre-flight inspection starts with draining fuel from each tank into a clear cup checking color, contamination and for water. I try to always leave the tanks full. Start up is reverse of shut down except electronics. Electronics are after the engines are running with oil pressure.

stevesxm

boats here ( sint maarten) REQUIRED to have mechanical fuel shut offs at the tank, cable operated from the cockpit in order to pass inspection . as for the other, marvel mystery oil in the fuel in the ratio as shown on the can solves mopst of the issues you describe.

CcanDo

stevesxm , Thanks for the report.

How does the cable system operate ? Is there a ball valve at the tank ? Does the valve sit on top of the pickup tube ? Is the valve attached to a bulkhead to combat stress fatigue ?

Pictures ? Thanks again !

stevesxm

truth is that i never DID put them on mine... just told them i did... but the ones i looked at were as simple and straight forward as you can get.... they went to napa and bought a lever action brass shut off w. 3/8 pipe threads and a handful of brass 90's and such and just screwed then into the top of the tank where the outlet is. rigged it such that it was "pull only" and ran a cable to a lever... some at the rear bulkhead and others i saw to an area near your knee on the side of the cockpit where you would stand at the seat... they are thought to be " war emergency" shut offs in case of fire. not "on off" every day sort of things. if you turn it off w/ the cable you have to access the valve directly to turn it back on.

not a bad idea at all i suppose ... i just look in my engine compartment at all the electric fuel pumps and all and have this vision of floating in the water one day watching the boat burn and sink thinking... " gee i really should have done those valves like they said....

stupid is as stupid does..