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Old 21-11-2008, 19:55   #16
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Racor at about half tank height, shut off valve at racor, Outboard squeeze fuel pump between tank and filter for filling racor and bleeding
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Old 21-11-2008, 20:03   #17
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Nauticatarcher. beat me to it..we just lost power here for about 10 seconds and had to of course reboot everything..happens here way to often..arrg!

but FWIW here it is

install an inline electric pump in the line as well as a valve..it makes priming soooo much easier...and yes your engines mechicial pump will suck right through it when its off so on need to run it all the time...his way is just as efective but the electric will keep you running if the mechanical fails so in a way its redundancy whic is a good thing.
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Old 21-11-2008, 20:09   #18
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Some electric fuel pumps can be used when off by the engine pump but not all. The electric pump needs to be after the filter or you will probably see it fail.
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Old 21-11-2008, 20:42   #19
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But before rushing and adding extra pumps (ie adding more to go wrong) one should make sure that one's engine is not one of the small marine diesels whose own lift pump will happily self prime, even with a lift on the suction side.

As one example, ours self primes with both the primary and secondary filters dry and with around 1-1/2 metres lift on the suction side from the low fuel level in the tank (our fuel is in the fin keel so well below the engine).

With respect to drain back from the fuel lines when changing the primary filter this is often negligible or nil. Partly because of their small volume but also depending on the configuration. Using our own case as an example, because it is all down hill from the engine lift pump to the tank top the lines appear to drain back into the tank whenever the engine is stopped as if I remove the primary filter element there appears to be only the spillage dribbles from the bowl/element. In any event, unless there are other than short runs the volume of fuel in the fuel lines of a small diesel is very little anyway and is easily caught in the container used for drips when removing the filter bowl/element. In those types of situations there is no need for valves about the primary filter and they only add to complexity (generally increased complexity => decreased reliability).

As DavidM says, there should be valves to cut off sources of fuel so connections into the tank should be valved. But in our own case we have not valved the leak off return from the injectors or the tank vent but have reduced the risk there by teeing the leak off into the vent at the tank so there is only one connection rather than the common two (I personally don't like to valve the tank vent due to the opportunity for shutdown of the engine through fuel starvation and subsequent confusion as to the reason - others may feel differently ).
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Old 22-11-2008, 03:57   #20
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Originally Posted by orion1 View Post
If I place a valve at tht top of the tank, the tube below the valve would drain when the filter element is removed. That might make it hard to get flow after valve is reopened, without turning over the engine.

Wish I understood the fuel system better. Need to read more I know.
Most engine mounted fuel pump will have enough suction to lift fuel 30" or so.

What engine do you have?

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Originally Posted by Chuck Baier View Post
I don't recall ever seeing a valve on a return line. Forgetting to open it could cause a problem. If you forget to open your intake line the engine will shut down at worst.
I've seen this on a few older production power boats. Not opening the return valve will cause a no start also.

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Originally Posted by Nauticatarcher View Post
Racor at about half tank height, shut off valve at racor, Outboard squeeze fuel pump between tank and filter for filling racor and bleeding
I try to avoid squeeze bulbs. They have a tendency to to not seal and leak air.

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install an inline electric pump in the line as well as a valve..it makes priming soooo much easier...and yes your engines mechicial pump will suck right through it when its off so on need to run it all the time...his way is just as efective but the electric will keep you running if the mechanical fails so in a way its redundancy whic is a good thing.
adding an electric pump can be a great addition. It has to be down stream of a Racor. Racors are designed to be on the suction side and not pressurized.
I worry about electric pumps as back ups when the mechanical fails.
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Old 22-11-2008, 08:31   #21
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Has anyone used a outboard squeez bulb on a diesel fuel line?
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Old 22-11-2008, 09:04   #22
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We have 3 gm 30 Yanmar, which is about five years old.
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Old 22-11-2008, 09:36   #23
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Quote:
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Not sure how some handle it offshore but under way in any seas large or small and that includes gales in the Gulf Stream we have never closed the valves on our fuel tanks. Not saying it should not be done just asking why. In all of the years I have been working on boats and there have been a lot of them, I don't recall ever seeing a valve on a return line. Forgetting to open it could cause a problem. If you forget to open your intake line the engine will shut down at worst.
You don't normally close your return line valve therefore you never have to remember to open it. The Coasties agree with me as well. The valve is only there in case something happens to your return line.

Its really a pretty good idea to have valves or caps for all the "holes" in your fuel tank except for perhaps your vent line. As I said, stuff happens and you don't know when you will have a fuel line leak whether it be a supply line or a return line.
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Old 22-11-2008, 09:37   #24
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We have 3 gm 30 Yanmar, which is about five years old.
The mechanical pumps on Yanmars do fail. They have a rubber diaphragm that separates the lubricating oil from the diesel fuel. If this fails and you use the backup electric pump. You can fill the crank case with fuel.
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Old 22-11-2008, 10:14   #25
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adding an electric pump can be a great addition. It has to be down stream of a Racor. Racors are designed to be on the suction side and not pressurized.
I worry about electric pumps as back ups when the mechanical fails.
Is there a bad side effect to pushing fuel through the filter?

My fuel system has an electric pump upstream of the filter. My original Racor filter developed an air leak (it was pretty beaten up) and when replacing I also installed a small pump, idea being that if another air leak developed in the upper fuel system then in an emergency we can push fuel through and keep running.
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Old 22-11-2008, 10:26   #26
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There are vacuum gauges on many fuel filters. The vacuum gauges measure how clogged the filter is getting. A fuel pump on the inlet side of the filter would add positive pressure to the filter defeating the purpose of the vacuum gauge.
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Old 22-11-2008, 10:55   #27
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There are vacuum gauges on many fuel filters. The vacuum gauges measure how clogged the filter is getting. A fuel pump on the inlet side of the filter would add positive pressure to the filter defeating the purpose of the vacuum gauge.
We also have a vacuum gauge on the filter. Your comment would be true if the pump were used for normal use but in our case its off most of the time but provides easy priming (including of the Racor) and an emergency air leak counter attack.
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Old 22-11-2008, 12:52   #28
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Has anyone used a outboard squeez bulb on a diesel fuel line?
Last two Yachts have had them and havr had know problems, as current yacht has manual lift pump in a position where its almost impossible to use without skinning my wrist its a god send
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Old 22-11-2008, 13:29   #29
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Is there a bad side effect to pushing fuel through the filter?
it won't flow. Racors larger than the 200 series have check valves in them
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Old 22-11-2008, 14:25   #30
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Is there a bad side effect to pushing fuel through the filter?

My fuel system has an electric pump upstream of the filter. My original Racor filter developed an air leak (it was pretty beaten up) and when replacing I also installed a small pump, idea being that if another air leak developed in the upper fuel system then in an emergency we can push fuel through and keep running.

The other problem with this set up is there is nothing filtering the fuel as it goes into the pump and in time it will gunk up and fail.
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