Racor fuel filters

[ip485]

I think I have a typical Racor fuel filter with a sediment bowl protected by a metal heat shield. There is a drain in the base and the top is secured with a large "wing" nut.

I open the bottom drain to remove the sediment, but inevitably this results in quite a lot of fuel emptying from the bowl. I then open the top and poor in some clean diesel to top it up again to prevent any significant amount of air getting into the engine. All in all I find it almost impossible to do without spilling some fuel and it would be even more awkward in a sea way. I know that Racor sell a "nice" replacement bottom drain with a grub screw but that doesn't solve the problem of topping up the bowl.

Is there a better solution?

I have not tried but in theory if I turn the ignition on will the pump refill the bowl once the lid has been released? The fuel tank is below the Racor so the pump is a lift pump.

 

[KellysEye]

> All in all I find it almost impossible to do without spilling some fuel and it would be even more awkward in a sea way

I used to put a bowl under the filter to catch the diesel and muck and have done that at sea. I never took the top off because our Racors had a pump on top to bleed the air out. You need to loosen the bleed screw on the engine and catch the diesel (not much) with tissue after the air comes out. By the way we had two filters in parallel with on/off switches in case one blocked, all Mobos have that.

>The fuel tank is below the Racor so the pump is a lift pump

The lift pump is on the engine Racors don't suck, so to speak ;-)

 

[TonyBuckley]

I've only ever lifted the top (Racor 500 something or other) to change the filter.

Drain from below and it just refills from the tank. No different than the engine taking the fuel away.

Why would air get in? Seems to have worked for me, but perhaps just lucky .

 

[rob2]

Much depends on the exact engine and tank installation. If the pump is on the engine side, then it won't be able to refill the filter housing - it will suck in air as it pumps the fuel out! My own installation has the filter (in my case a CAV) half way up the tank with the fuel take off from the bottom of the tank, so if the fuel level is sufficient, it will fill the filter housing if I open the bleed screw. If the level were below the filter, I would have to open the injector pump bleed screw and pump until the air has been expelled there.

Rob.

 

[TonyBuckley]

Much depends on the exact engine and tank installation. If the pump is on the engine side, then it won't be able to refill the filter housing - it will suck in air as it pumps the fuel out! My own installation has the filter (in my case a CAV) half way up the tank with the fuel take off from the bottom of the tank, so if the fuel level is sufficient, it will fill the filter housing if I open the bleed screw. If the level were below the filter, I would have to open the injector pump bleed screw and pump until the air has been expelled there.

Rob.

Makes sense. Only ever had the filter below the tank and just let gravity do its work. Makes it easy but accept not every boat can be arranged in such a way.

 

[Daydream believer]

I have put a bulb primer in the system before the filter
Open the bleed screw & just pump fuel through.
You need a diesel one for diesel of course

As well as that I have fairly long fuel lines each side of the CAV filter.
The filter ( which is pretty inaccessible in its fitted position) is bolted in place with butterfly screws on studs, so if I want to change it ,I unbolt it & place it over a bucket

 

[donm]

I put in a Racor 500 because it is so simple to change the filter - just undo the cover, lift out the filter and put in the new one. To drain sediment try using a clear plastic bag - place it around the filter body and undo the sediment bleed screw catching the fuel in the bag. I also put in an in-line bulb primer to make bleeding te system easier but with the Racor it should not be necessary unless you have bled off an enormous amount of fuel as the filter must hold around .5 litre!!

I think I have a typical Racor fuel filter with a sediment bowl protected by a metal heat shield. There is a drain in the base and the top is secured with a large "wing" nut.

I open the bottom drain to remove the sediment, but inevitably this results in quite a lot of fuel emptying from the bowl. I then open the top and poor in some clean diesel to top it up again to prevent any significant amount of air getting into the engine. All in all I find it almost impossible to do without spilling some fuel and it would be even more awkward in a sea way. I know that Racor sell a "nice" replacement bottom drain with a grub screw but that doesn't solve the problem of topping up the bowl.

Is there a better solution?

I have not tried but in theory if I turn the ignition on will the pump refill the bowl once the lid has been released? The fuel tank is below the Racor so the pump is a lift pump.

 

[TNT]

The racor's have a large T bolt in the center, I use a large syringe to refill them through the T bolt hole. but as long as there is a little diesel in the bowl and the engine is started on about 1200 --1500 RPM the pump will pull the diesel through before the air kills the engine, it may miss a little but it will clear.........usually.!!

 

[ip485]

Thank you all so much some very helpful replies.

You are of course correct the pump in my case must be on the engine side and the tank is below the Racor hence gravity cant do its job.

I really like the idea of the bulb and bleed screw.

If it were possible replacing the T bolt with a system that would have a bleed valve for the air and a valve to allow fluid to be pumped in using a small pressure vessel would be perfect. Perhaps I can rig up a garden pump sprayer, remove the T bolt and introduce the fuel that way.

 

[superheat6k]

I have various dripless instant connectors upstream of the Racor, tank drain, and spill return cross connection. Then using an electric pump with inline separator filter I can move fuel in numerous directions whilst polishing it. One way round the pump drains the Racor to change the element, the other it primes the filter, back flushes the fuel pickup if any muck gets picked up and also partially pressurises the system right up to the on engine fuel filters.

I run it as a simple polisher for about 1 hour per tank per month and I do not have any significant water in my fuel nor fuel bug. Nor do I have to brim my tanks over Winter.

 

[prv]

Plus one for outboard-style squeeze bulb immediately after the tank. It lets me push fuel through the system, including to refill a new filter after changes. I just open the bleed screw and squeeze the bulb until fuel starts to emerge. Hold a bit of kitchen roll around it and no diesel need be spilled.

I believe all outboard bulbs are suitable for diesel; it's less vicious than petrol. But the packet should say anyway.

Pete

 

[ip485]

I have been giving this some more thought.

Racor do a rather nice drain with a tap on the drain for the bottom of the centrifuge housing. I know it is £40 but it seems a good solution to draining out the bottom of the centrifuge with as little mess as possible. I have ordered one.

So that leaves the problem is getting fuel back into the bowl to avoid introducing too much air into the system.

The engine is 120 HP turbo charged. With the in line bulb solution do people think this will cope with the fuel flow rate without introducing a restriction?

The other solution I came up with is if there was a tap type valve that replaced the copper handled screw on the top of most Racors fuel could be introduced from a little pressurised bottle or even a bottle held above the Racor without having to even open the handle. It would need to be drilled with two small apertures on to introduce the fuel and one to let the air out. Maybe they already exist?

 

[smithy]

Fitted a bulb to mine and it made bleeding much easier. Wouldn't worry about fuel flow, ever seen how much a big outboard burns!