Fuel Polishing

Gonzo, when you want to change the filter and the fuel is above the cannister, without isolation valves you have a lot of fuel to deal with as it drains lines, etc.* Isolation valves just upstream and just downstream of the Racor lets you just drain the Racor body, not the whole system.

Nah... I close the exit valves on the tanks and it does fine. After replacing the filter, I can just crack one open to refill and it's less than 2' away. On my little boat, It's not a huge deal. I want to keep hardware to a minimum at this stage.

And please... Call me Tom.

The plant/shop also*uses Loc tite.**You*can buy at most auto stores.* The PSI of a fuel system is usually under 10 PSI*the Walbro fuel pump is 7 PSI.***

If your fuel lines are 1/4 or 1/2 the pump does not have to be high gph as the line will are the limiting factor.* I usually polish during a wind storm when the boat is rocking a rolling to stir up the tank a bit.* If you already have filters you do not need to by bigger or new ones.*
Best to have valves at the filters so the lines are not drained when changing*the filter.* If not then you might have to bleed the lines also.* Make sure you fill the filters to the top.* I have a*1/2 gallon fuel can*to fill the filters.* *

Well, got down to Skinny Dippin' yesterday to get a closer look at things and measure the space I have for the fuel system redo. Looks like there is going to be challenges. Not the least of which is that the fuel returns are only 1/4" hard tubing. While it DOES look like they COULD be changed to a 3/8", they are in pretty tight quarters and it won't be easy to get to... if at all. However, it looks like there MAY be a few other places where a fitting could be added. I don't know that for sure, so when I get my digital camera back, I'll shoot some pics for y'all.

Anyway, another interesting thing I found was that the return from the main engine went into one tank, and the return from the genset goes into another... THAT explains a few things. There is a mish-mash of hard pipe, rubber fuel lines, and some braided line throughout the whole system. It was quite an awakening. Now it's time to fix it.

What is the 1/4" return line going to do to a polisher's capacity? Is it going to junk the whole polisher project if I am unable to change it out to a 3/8"? That said, should I just look at putting a portable rig together that I can just pull out, tap into a fitting that I add when I upgrade the filter system and then just feed the return into the filler hole?

Tom-

Tom, the flow rate of 1/4" is around 40 gph with diesel.* You can still polish, but I would not bother to install larger than a Racor 500 with a Walbro pump.* This might be less than optimum, but if you use it when underway in the slop, the motion of boat will agitate the fuel, stir up anything that has precipitated out of the fuel and as long as you are diligent in polishing whenever possible should be fine.

Sounds like you need to combine the tanks or install a day tank into which returns from the genset and main flow.

If you would prefer to use a 120 vac pump (that would be my choice), there is a ProCon vane pump that will match the flow potential of your 1/4" line.* The part number from Grainger is 6XE79.* You definitely only need the 1/4 hp carbonator motor to drive that.

-- Edited by Delfin on Sunday 16th of January 2011 10:01:50 PM

Any objection to just getting the next size up pump anyway (6XE80) with the 1/4hp motor and a Racor 500 anyway? If I can start with this and use it with the 1/4" returns for now and change then out to 3/8" in the not-to-distant future.

-- Edited by GonzoF1 on Tuesday 18th of January 2011 01:44:47 PM

If a PD pump does not*have a suitable sized discharge line, it will fry itself or blow fuses very quickly. You want no restrictions on the line.

PD pump?

I think that until I can get a suitable size return, I could still route the output back into the tank via the filler hole.

sunchaser wrote:

If a PD pump does not*have a suitable sized discharge line, it will fry itself or blow fuses very quickly. You want no restrictions on the line.

Click to expand...

Tom, the advantage of the motor and ProCon pump I indicated is that the pump has a pressure bypass and the motor is sized to turn the pump against that pressure.* You can literally close the valves down (or forget to open them) and everything works just fine, as long as the piping can handle the 250 psi bypass relief pressure (not recommended).

So you don't have to worry about burning the motor out and there is no reason, within reason, not to bump the pump up in size to 60 gph to meet future pipe sizing.

*

Delfin

My comment was intended for the non bypass models, such as the 3 Gracos I have for fuel transfer and oil draining.

GonzoF1 wrote:PD pump?

Click to expand...

Positive Displacement. Each revolution or stroke of the pump discharges a fixed (swept) volume of fluid as opposed to one which discharges a volume that varies with speed or head.

*

The parts have started to come in. Let the building fun begin!!!

One pic is the final drawing and the other is the mock-up. Including the pump, motor (1/4 horse w/60 gpmpump), Racor 500 with gauge, and the check valve in the upper right. The cardboard templates are my two existing 500's that will become a two-stage filtration for the main and genset.

The whole thing will eventually be mounted on a piece of 1/2" King Starboard that will be installed in a way that will give me a quick way to remove the entire fuel filtration rig as a single unit for ease of service.

The next step is to bolt it all down and take it out to the local hydraulics warehouse and spend an hour plumbing it all together.

Thanks for all the help an advice and I'll keep you posted.

-- Edited by GonzoF1 on Tuesday 25th of January 2011 03:35:05 PM

Can't quite follow the diagram, but flip the motor and pump over.* Always have pumps below the motor so if there is ever a seal leak, it doesn't take out the motor as well.

Really? That will mess up the layout pretty substantially. But let me see what I can do. I've been working on the layout for a while and this is really the best way.It minimizes some of the extra spaghetti of tubing by having the fuel tank inputs on the lower side and the tank returns on top. Still, let me try a few things.

Let's try and explain the plan.

1) The bottom left has the input manifold with two tank inputs. Basically, so you can select WHERE the fuel comes from with the ability to easily add a third day tank in the future.

2)The 3-way valve bottom center allows selection to send the supply to the 2-stage filtration on the left or to the polisher rig on the right. (Having just this very second that I did not account for the fact the Racor 500 input is on the right... back to the drawing board )

3) The exit of the 2-stage filters will have a "T" to split it to main engine and genset.

4) The input to the Racor on the right (polisher) has a 3-way valve to allow you to bypass the filter for fuel transfer needs only.

5) After passing thru the filter and pump you can then use the manifold on the top right to select the destination tank (with the ability to add a day tank to the mix later).

6) Also at the far top right (not noted with an arrow) is the incoming return fuel from the engine that passes thru a check valve before it enters the manifold.

Did all that make sense? I'll post the new layout once I get it together and fix my screw-up and try and make the pump be on the bottom.

I'm having a Griffin G500 fuel filter/water separator (not shown) added to the fuel polishing circuit of the Coot's fuel system. *Now, maybe I'll get rid of water and fuel-junk both coming and going.* (Should I*also get suspenders to backup my belt?)* The addition of the polishing system cost*less than a*fuel fill-up.

Looks good.Is that what you have now or are building?


-- Edited by GonzoF1 on Tuesday 25th of January 2011 07:06:02 PM

GonzoF1 wrote:

Looks good.Is that what you have now or are building?


-- Edited by GonzoF1 on Tuesday 25th of January 2011 07:06:02 PM

Click to expand...

That's what Seahorse Marine is building for me, but without a genset.

*

Tom, I think it does, although it will help to see it drawn out.

That looks like the Capt will set up. Very effective.

Gonzo,
What (pump, source, cost) did you use?

Tom, now I understand the drawing - I should have paid closer attention.* There is a likely problem with your layout I think you need to correct.* As drawn, the suction from the Procon pump will be working against the suction from the engine fuel pump.* Move the supply for the engine to the output side of the Procon and you should be fine.*

One more thing to note - the pump will move the amount of fuel it says it will because the split phase motor will spin the stamped rpms (if not, the thermal protection will cut out or the breaker trip).* Consequently, depending on the size of plumbing on the suction side the vacuum gauge may read higher with a clean filter than it would with freer flow, or a pump that bogs down as suction lift increases, which this pump will not.

I'm not sure I understand what you are saying. Are you talking about the return from the injector pump?Or are you saying that it will suck fuel away from the engine.

If it is the first, the return FROM the injector pump goes through a check valve at the top right.

If it's the second... The system is not designed to run simultaniously while the engine is running. The 3-way valve in the lower-center of the drawing is to select the fuel to route EITHER to the engine OR the polishing rig. Not both.

DaddyO... Pump and motor are both from Grainger. Pump is part# 6XE80 and the motor is # 5XB85. Both together cost about $190

Tom-

If you're not going to polish fuel while the engine is running, then there isn't an issue.* I am assuming that the two Racors on the left are the secondary filters supplying fuel to the injector pump.* If so, you don't want the injector pump to be working against the polishing pump but if you don't run them at the same time that's not a worry.* My suggestion to take off the injector pump supply from the output side of the Procon also assumes that the Procon will pass the required flow whether it was running or not, which as I think about it, may not be the case.* A day tank would solve all of this.

Incidentally, if you have to mount the motor with the pump above, it's not the end of the world, it's just a best practice so that if a pump leaks, it doesn't leak into the motor.

Delfin wrote:

If you're not going to polish fuel while the engine is running, then there isn't an issue.* I am assuming that the two Racors on the left are the secondary filters supplying fuel to the injector pump.* If so, you don't want the injector pump to be working against the polishing pump but if you don't run them at the same time that's not a worry.* My suggestion to take off the injector pump supply from the output side of the Procon also assumes that the Procon will pass the required flow whether it was running or not, which as I think about it, may not be the case.* A day tank would solve all of this.

Incidentally, if you have to mount the motor with the pump above, it's not the end of the world, it's just a best practice so that if a pump leaks, it doesn't leak into the motor.

Click to expand...

The two Racors on the left are the PRIMARY filters to supply the engine.

How would a day tank solve anything? I am missing something in your logic.

Otherwise, things like the pump-over-motor being an issue (or better yet the non-issue) would be nice to know before you say it should be changed and I spend all night last night doing a full redesign of the rig. Just sayin' (just ribbin')

*

You are correct on the primary/secondary designation - my bad.* Tom I sent you an email with my cell number.* It's easier to talk than write, so give me a call.