Diesel shut off valve

[rivonia]

Can anyone out there give me a quick answer. We have a solaris Catamaran with Twin engines both Volvo 2020's. I have searched and not found a Diesel shut off valve. My question is; Should there be one? we have two seperate diesel tanks as well (dont ask me why). We had the engines fully serviced and both run very sweetly. Awaiting replies

 

[Cliveshep]

Assuming the fuel connection is a dip tube type with top-of-tank outlet I guess it is not strictly necessary unless you want an emergency stop via fuel starvation (can't think why), as with engines-off fuel cannot flow because generally the fuel system and lift pump on the engines are higher than the top of the pipe exiting the tank. If your tank outlets to system are from the bottom of the tank then yes, you must have one.

 

[oldsaltoz]

Our cat has twin engines and tanks also, we have shut off valves between the tank and fuel filters, I suspect you have one or the filter is above the tank.

Most cats have twin tanks, we also have change over valves on the fuel return lines used to maintain levels in both tanks.

Hope this helps.

Avagoodweekend......

 

[rivonia]

Thanks to both replys, it leaves me a tad confused as it would appear to contradict each other. I like the idea of a valve before the filters=diesel to the engine. I also like the idea of being able to use one tank and then the other. My problem is there are so many tubes/pipes running all over the place. It looks as though it will cost me again to get the mechanic back and fit accesable valves. I still wonder if it is still necessary to fit any at all?

 

[willie4646]

My Oceanic 30' Cat has two separate tanks (not connected), both have shut of valves fitted between the tank and the pre filter/watwer trap.
Willie

 

[Cliveshep]

The posts do not contradict one another. What Oldsaltoz is saying is that he is able to switch between tanks to run his engines rather than have one tank for one engine which is why he would have change-over valves as well as an isolating valve between his tanks.

He also mentions the filter higher than the tank which brings me back to the ground rules I outlined in my post responding to your query as to whether or not you NEED shut-off valves.

His system would need valves to control how he draws fuel from his tanks, if you don't have his system with change-over feeds but each tank solely does one engine my ground rules still apply.

The idea is to shut off fuel if a disconnection in the system anywhere would permit fuel to freely drain from the tank, as with a bottom fuel outlet. This is why you MIGHT need valves if this is the case with your own boat.

If your outlet is at the top of the tank but lower than your filter and there is no changeover system you don't NEED a shut off valve to control fuel spillage, but MIGHT still want one if you felt a need to shut off fuel to starve an engine into stopping.

Does that clarify for you?

 

[NorthUp]

You may not need, but should have shut-off valves-
1. engine space fire to cut off fuel
2. even if fuel line exits top of tank, it will probably syphon fuel out at engine in the event of a leak at engine.
3. contaminated fuel? you can isolate one tank.

 

[rivonia]

Hello to all of you. Thanks a lot. I now understand and it is very clear. No I do not require shut off valves, however what I am going to do is fit one before each pre-filter.
Thanks again

 

[cliff]

If you are going to fit shut off valves I would fit them at the tank outlet rather than at the pre filter - that is assuming the prefilter is in the engine bay near the engine and the fuel tank is elsewhere (remote tank) - in the (extremely remote) chance of an engine bay fire you may be able to shut off the fuel at the tank but not if the valve is at the prefilter in the engine bay.
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