Changing Fuel Lines

[JC]

Hi Guys. I have a question. =) I am removing my racor 500 and am adding two new filters instead. I am adding a FF5013 as a "bulk separator" (30 micron) and am adding an FS1000 (10 micron) as a second filter before my engine filter. I will be changing all fuel lines too. I have been having fuel problems and dont want to go thru this again.

Can somebody give me some advice or pointers on hoses/fittings/etc...

I notice the hose from the fuel tank is lined with some protective covering but the return lines look like regular rubber hoses. Do you use some tipe of sealer at the fittings? What characteristics do I look for in the hoses??

Thanks for your time and sorry for such a simple question...but I rather ask and do it right that find out later.

JC

[Bruce]

Check and make sure 10 micron will not starve the engine. (you don't specify make. Since you note a 500 I am assuming diesel)

On hoses:

Least expensive
CG approved red strip fuel hose. Will use hose clamps. All fittings should be put together with Methacrylate Ester (Tuff Gel, not Teff gel). Not teflon tape.

Most expensive
CG approved aeroquip or parker hose that uses two piece fittings and are made to length and fittings applied at the hose shop.

Much, much more expensive, harder to work with and less forgiving if your short or long.

If you use any type of flare fittings, use copper cone washers to make sure you get an air tight seal.

[JC]

I was all day at the boat. Changed fuel lines from tank and installed 2 new filters instead of the Racor 500. 2506bta engines.

Took out the boat for a test. Port engine not getting full RPMs....seems like a fuel restriction problem. I go down on the gas and the engines goes off. It got air in the fuel system.

I get back to the doch on the sbd engine. Seems like it getting small variations on RPM's. You can barely see it on RPM gage but you can hear when the engine gets more fuel. Tye to the dock. By now it night time. When we put the engine back to go to the buoy now the stb engines gets full of air??

I was so frustrated I just came ack home. An hour away from the boat.

Where did we go wrong?? Maybee air leaks at the connections?? Whats the easiest way of getting air out of engines after changing hoses. I had bleed at the bleed screw by the lift pump untill I could see fuel coming from hoses. I assumed al air was out. Got the boat to 2200 rpms. Could it be it had air at that moment or it probably was getting air from fitings???

Help please!!

JC

[Capt. Mike Holmes]

As Bruce stated, 10 micron is too small for a filter on the suction side of the engine fuel pump - use 30 there. 10 micron or smaller works on the pressure side just fine. I run 30 micron filters in 900 series Racors on my 6BTA's - more filter capacity seems to work better than tighter filtration. To bleed the Cummins, after bleeding at the filter, crank the engine and crack each injector nut, one at a time, to let air out. If the engine won't crank, crack the nut and turn it over until you get good fuel flow out, no apparent bubbles. Then go out and run it, because, as Vic says, you can't work all the air out of these engines without being under load. They are actually pretty forgiving, most of the time. I have electric "boost" pumps after my Racors, and can bleed the system with these on without cranking.

[Mikey]

Capt Mike,
AS the tank goes in this week your note on the electric "boost" pump (s) is interesting. What did you use, one pump per engine? Gime a scoop.
Tanks, Buckwheat
Mikey

[Capt. Mike Holmes]

Mikey. I'll see if I can get the name and model number of the pumps today. They are big 12v of a type the dealer says they sometimes use as main fuel pumps on big Detroits. I have one per engine. I really wanted them in front of the Racors, to be able to just pump fuel in after changing filter elements, but the manufacturer strongly recommends a filter in front of the pump. I could get the same result with sone creative plumbing, just haven't done it yet. These pumps will free flow if they go out, or lose power, they are wired to the ignition circuit, so they come on with the key yo pressure up the lines. The original intent was to help the lift pump deliver enough ful to the engines, as my mechanic friend always reminds me that pumps usually push better than they suck, and the fuel tank is a long way from the engines. They seem to be able to push fuel through the manual lift pump even when the engine isn't running, to make it easier to bleed the line through the screw on top of the engine mounted filter. By the way, be careful buying Racor elements from Boat Useless. Down here, they only stock 2 micron filters, - 10's and 30's are special order. A 2 micron will plug on the suction side just from the red dye in the fuel, it seems.

[Bruce]

Walbro, best pump on the market, good company to buy from.

I would use one for each engine.

http://www.depcopump.com/catalog108/41.pdf

[Capt. Mike Holmes]

Think that's what I have, black housings, brass plate on the end? They have worked great, I wouldn't want to do without them.

[Mikey]

Bruce,
Before or after the Racors? If the pump craps out and is after the Roacors and deposits parts in the fuel line . . .then what? Those pumps (6092) says 1 gpm. IS that sufficient for 6BTA 300's?
Mikey

[In Memory of Vicroy]

Mikey - a gallon a minute is plenty. Full bore you will burn about 12 gal. per hour per engine and recirculate about the same back into the tank. 60 GPH is plenty. Put the pump before the Racor, that way you can use it to prime the Racor when you change the filter element. Just leave the top of the Racor loose and turn the key on and wait for the fuel to come out from under the top of the Racor, tighten it up and you are done. No need to pour diesel into the body out of a can. My genset is set up that way and it is the cat's meow......

UV

[Capt. Mike Holmes]

The pumps have a screen in the inlet that I don't think can be changed. If they don't have a filter in front of them, the warranty is void, and you might have to throw them away early. I wouldn't worry about pump parts in the lift pump as much as crap in the pump inlet. I've been running mine like this for over a year, seems to help performance a bit.

[Bruce]

Mikey,
After the racors as the pumps could clog from debris. Sorry UV.
They will refill as they suck fuel thru the system to prime secondary.

After changing filters and restarting engine, leave pumps on for 5 minutes while engine runs to aid in removing any air.

[Dave Kosh R.I.P.]

Well I can only speak for my self but I've been using 2 micron filters on my Racor 500's for the last six years without any problems. I have the 250 Volvo TAMD60C's. Change them and clean bowls every six months. Guess it depends on where you get your died Diesel. Why does mine works so well with the 2 micron? Dave K

[TailhookTom]

I have same engines as Dave and have been doing the same thing. I have Algae X units in line before the Racors, but I have never had a fuel problem with my filters being too fine.

Tom

[Bruce]

The reason for a return line in a diesel is that it does not use all the fuel that is fed to the injection system.

This can be because the fuel is also used as a coolant or that more is delivered than what is needed.

Not all engines circulate the same amount of fuel.
Some dribble out the return. Some gush.

The amount of fuel the engine manufacturer delivers overall to the engine determines the micron rating of the filter.

High flow engines will be restricted with a 10 micron filter and can lead to failure of the primary fuel pump or create excess pulsations in the fuel system leading to questionable performance at times.

That is why when posting questions or reading posts, specific engine makes are important.
Some things, especially engine requirements are make and model specific and cannot be "across the board" for all engines.

Always check your manufacturers requirements for your engine.

An example would be say on a Detroit 6V-92 would burn 50 gal/hr at cruise but will circulate 90 to 110 gph. A 10 micron would not allow the engine to get past the howdy stage.

[JC]

Hi Bruce. I installed a 2 stage filtering system as per Tony Athens (boatdiesel forum) recomendation. I have a "bulk separator" as my first filter which is a 30 micron filter that is also a water separator. It has alot of crud holding capacity. It is a filter that is used in the fuel dispensing industry. As a second filter I have a Fleetguard FS1000 which is a 10 micron filter also a water separator. It is way bigger capacity/volume wise that the Racor 500 I was using.

After these 2 "primary" filters diesel is fed to engine filter which is the cummins recomended "on engine" spin on filter.

I did this change as I had problems with my fuel and the racor 500s getting clogged to quickly. These filters are supposed to give me a long term solution to my fuel filters and reduce service intervals.

I have since cleaned out the fuel tank and added Biobor at every fuel up to prevent future problems.

Turns out on Stb engine had an air leak. I noticed cause after beaing left sitting the engine would not start. I sealed off every connection starting at the tanl and have no problem on that engine now. I will do the same with port engine.

Will keep you posted. I read in you post 10 micron is too small. Isnt the on engine filter a 10 micron filter???

Sorry I have 2506bta engines.... =)

THanks,

JC

[Capt. Mike Holmes]

JC, the engine mounted filter is AFTER the mechanical lift pump, on the pressure side, so it can be as tight as 2 microns on some engines with no problem. Remember, pumps push stronger than they suck, usually. 10 micron filters will work on a 6BTA, but will clog more quickly than a 30. Maybe this is good as far as cleaner fuel, but it doesn't seem to be necessary.

[Bruce]

Jk,
Engine model specific on the 10mic.