Simple Fuel Poliishing

[83GB]

My Walbro pump has a fine screen filter that clogs easily when it is before main polishing filter... ask me how I know..

 

[Grey Goose]

I am involved with a commercial fuel maintenance company. The smallest tank we maintain is a 7 gal sailboat, the largest tanks run in the hundreds of thousand gallons.
I would ask about your “polishing filter”. Seems this isn’t anything more effective than a dual Racor set-up.

 

[catalinajack]

Aren't most fuel pumps after the main filters? I have Lehmans and the on-engine mechanical pump is after the primaries as are my Walbro pumps now.

I would put the pump ahead of the filter. They push better than they pull.

 

[SteveK]

Aren't most fuel pumps after the main filters? I have Lehmans and the on-engine mechanical pump is after the primaries as are my Walbro pumps now.

This becomes confusing as the filters mounted on the engine were the primaries and they are after the lift pump, before we add a Racor ahead of the lift pump. Now Racor is primary.

My engine mechanical pump is ahead of the engine mounted filters, otherwise I could not bleed the air out.

 

[rgano]

You might consider some additional plumbing so that your polishing pump can act as a lift pump should the engine lift pump fail... just a thought

My polishing pump was a separate system and was not plumbed to supply the engines, BUT there was a small "filter priming" pump installed before all the filters which could be used to presurize the fuel delivery system. I had to use it a couple of times to run a Lehman 120 suffering from air ingestion through a crimped Racor tee-handle o-ring, which took awhile to find.

 

[Woodland Hills]

The simplest polishing system is a Detroit Diesel in normal operation!

 

[Tim]

Pump location

Yes you are correct in having the pump after a filter. My polishing pump was after the racor. Two tanks and a single Ford L. I installed a three way valve after the pump so fuel oil could go to the other tank or to the lift pump and then the engine filter.

 

[FF]

"I would put the pump ahead of the filter. They push better than they pull."

The reason this is not the best procedure is the pump will shred the water (emulsify it ) which is harder to filter .

If the fuel box has a bottom drain or a pump to lift gropsch from the bottom using a de-emulsing product will help clear the fuel, but still do nothing for the tank walls.

 

[LiquidTherapy]

Fuel Polishing Thoughts - After fuel goes thought my 30 micron Racor primary filter that does a great job of filtering sediment and any water that accumulates and then flows through two engine mounted filters of 10 microns each before getting to the injector pump -I'd say that fuel has been polished. The excess fuel not used by the injector pump gets dumped back into the starboard tank only. So, I'd say my starboard tank has polished fuel that eventually gets sucked back though for another round of polishing. Is a stand alone fuel polishing system really needed?

 

[Roger Long]

Is a stand alone fuel polishing system really needed?

That depends. Our cruising is presently on the well traveled parts of the east coast where fuel quality is quite good and a polishing system is well down the list of future improvements. If you do think you need one, this is a concept although I should have been clearer in the OP that it is intended for easy retrofit in cases where it would be expensive and difficult to add additional piping connections to the tank(s).

We have had an engine shut down and long day of delay and fuel system maintenance that probably would have been avoided if the boat had a polishing system. Would the installation have been justified by that one event which took less time to recover from than its installation would have taken? Good question. If the engine had shut down while I was running Manasquan Inlet after a slight miscalculation last fall, the answer would be pretty clear.


The nature of filtration is that your current system is passing a lot of particles that are larger than 10 microns. It's just dramatically reducing the number. You are experiencing slightly greater wear on injectors and injection pumps than you might. Modern diesels, especially the common rail ones, are more sensitive to this.


I got interested in on board, continuous, polishing when I was planning on a circumnavigation of Newfoundland. I did get a load of bad fuel in New Brunswick and left a big bag of cheap filters in a trash can. If those had been Racor filters, they would have cost as much as the pump and filter combined. I was in a place where alternatively getting the boat running again would have been difficult and expensive.


Do you need a system? Only you can answer that.

 

[FF]

"Do you need a system? Only you can answer that."


If the first purchaser of the boat demanded a proper fuel tank with deck fill and bailable sump , instead of accepting a box for fuel ,,,we would not be having pages of "fuel polishing" discussions.