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-   -   Fuel Filter Placement (http://www.sailnet.com/forums/gear-maintenance/51086-fuel-filter-placement.html)

TxLnghrn 02-02-2009 06:09 PM

Fuel Filter Placement
 
Due to some recent difficulties (Thank God for Tow Boat US), with our fuel system, I am thinking about upgrading our primary fuel filter from the current Racor 120 series spin on to a Racor 500 series. The problem I am facing is that the current location for the fuel filter doesn't allow for the 12-plus inches required for the 500. Would there be a problem with mounting the 500 with it's inlets approximately 8-10 inches above the top of my fuel tank, roughly parallel with my injectors? The engine is a Yanmar 2gm20f. My main concern is whether the pump would have a problem pulling fuel up against gravity before it gets to the high pressure side.

Michael

jason3317 02-02-2009 06:39 PM

Tx -

Why do you want to go bigger? The 500 is overkill for that engine, although there are definitely bragging rights involved.

I am thinking you got screwed by a clogged filter by your post?

Rockter 02-02-2009 08:36 PM

Fit a pump to pressurise your system?

I fitted one of the Walbro 2403-1 pumps.

It's a 5 psi pump, and should work for you. Thereafter, downstream of the pump, air never can leak in again. Fuel can leak out, but then you see the leak and you can see it and fix it.
.

gc1111 02-02-2009 09:10 PM

Those little on-engine fuel pumps can exert a LOT of suction. The bottom of my fuel tank is several feet below the pump and it never had problems sucking the tank dry :-)

That said the suggestion for an electrical pump between the tank and the filters has a lot of merit. It also makes bleeding the filters after changing the element very easy.

badsanta 02-02-2009 11:12 PM

It is my understanding that the racor 500 is to be used under suction and not made to be pressurized. So put the pump between the racor and the engine.

bwindrope 02-03-2009 12:10 AM

Not filter size problem
 
Hi Michael,
I sympathize with your problem but agree with Jason that it is not a filter size problem. I have a Gulf 32 with a 70 gallon diesel tank and use a Racor 15S 2 micron. It is rated for something like 15 gallons an hour when my 4 cylinder Universal 5432 uses less than 1 gallon an hour at full throttle. I just happened to change my primary filter and after 150 hours it was nearly like brand new. I change mine once a year just to be extra careful. Your smaller motor uses even less fuel and so filter size is definitely not your issue.

Long story short, your problem lies elsewhere. What I love about diesels is that they are so darn easy to diagnose, especially when compared with the modern gas engine.

I also have a Walbro pump as my electric pump, and it lies between the filter and the engine. Although my Racor has a primer pump on it to fill the system at filter changes, I have used the electric pump to do my own fuel polishing, which you may want to do as well.

Anyway, just my two cents that I wouldn't think your problem is at all related to the size of your Racor. Good luck, and keep us posted. :)

badsanta 02-03-2009 12:18 AM

What ever filter you go with. it sounds like you have crud in the tank and you should fix that first. If not a large tank you could drain, flush and fill with new. If a larger tank you may have to have some one polish the fuel. What they do is pump it out and filter it and replace the cleaned fuel.

blt2ski 02-03-2009 01:14 AM

I use the Racor 120 also with my 2gm20f on my Jeanneau. I personally can not see using a bigger filter! As others have said, I think there is another issue, ie junk in the tank, bad fuel that last fill up etc. Those are the usual reasons for clogging fuel filters with diesels, be it in my pickup, dumptruck, trackhoe, bobcat or sailboat!

marty

Rockter 02-03-2009 04:23 AM

The Racor filter will have a pressure rating somewhere, both burst and collapse. I looked for it but could not find it. Racor should know.

I reckon that 5 psi burst loading is not a lot for a filter housing to take, surely?

I still reckon that the pump should be upstream of the filter. Your filter is less likely to clog, as it is pressure driven. Your lift pump will not have to do work at all. In my own set-up, I can switch off the electrical charge pump and the motor still runs. The pump manufacturer very kindly has built a wee by-pass port into the pump. They are not expensive, at close to $80.

This electrical charge pump set-up is not for everyone. There is an added fire risk if you spring a leak, but fuel leaks out and not air in, and you will see it. When you stop the motor, you can leave the pump on and listen for the wee "rat-tat-tat" as the pump maintains pressure. It is a good leak test. Older motors tend to get a wee bit leaky on the fuel lines sometimes.

It certainly keeps air out of there, and the motor really cannot draw air without you seeing the fuel filter level dropping. In the past, I could draw air downstream of the filter and not see it. and not see it. I had that happen a few times in the past, and it's a heart-stopper as the motor slows, and coming into a harbour it is bloody awful. It does not happen now.

Bleeding your fuel system is much easier too with an electrical lift pump.
.

celenoglu 02-03-2009 04:33 AM

The fuel pump on the engine will handle this height. Install the filter where you can, but make sure you bleed the system. After all the hoses and the filter is full with fuel you will not have a problem.


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