question re: dual racor 500's on Mainship 34

[newbernbuck]

Hello and thanks all for the knowledge I've found on here.

This mainship has (2) racor 500's on it that are plumbed so that either one can be switched to pull from either or both tanks or that both filters can be used at the same time. The way the previous owner used it was both filters pulling from both tanks all the time. As these racors I'm guessing are likely oversized anyway, my logic is telling me to switch valves so that only one filter is used and then use the other as a backup. Thinking that both having so little flow that they are not taking advantage of the 'turbine' effect. I am rebuilding both filters at the moment and they are pretty nasty in the turbine area in particular.

I apologize if this has been covered, thanks

 

[markpierce]

I use one of my two Racors at a time.

 

[dhays]

I would use one at a time. That way, if something happens and you get a whole bunch of crap in your filter and clogs it up, you can switch to the fresh filter and use it while you change out the other filter.

 

[Drake]

We always run one one filter, keeping the other as a backup. That's the point of having two. If one clogs, you can switch to the other underway.

 

[obthomas]

I have one racor for each engine. My port and starboard fuel systems are separate. Each system has a transfer pump and can move fuel to the other side. My racors and transfer pumps double as fuel polishing systems also.

 

[Ski in NC]

If you have dual filters for one engine, it's a good idea to run on one and leave the other valved out, as others posted above.

Also a good idea to occasionally swap even before they clog, that way you know the standby filter is ready to go.

Also, even if you don't use the filter, it does age out based on time alone. So change it once a year or two even if not used.

 

[Busterbrown]

I also have a duel set with vacuum gauge. I use a 2 micron on primary side and 10 micron on backup. FL 120 2714

 

[Keysdisease]

Many of the Mainships were plumbed with a Racor as a secondary filter with the primary being engine mounted on the Perkins. If this is the case than I would re-plumb to only go through one Racor and keep the other plumbed as backup as suggested.

But, if there is no engine mounted primary filter then a previous owner may have plumbed the 2 Racors to act as primary - secondary with different micron filters as mentioned. In this case I would continue as plumbed.

As you are in the turbine or bowl area already, be sure and unscrew the diffuser at the bottom of the filter where the raw fuel comes into the bowl. there is a metal ball (8 and 9) inside there and that chamber can be clogged up pretty good if you don't know to look there.

 

[Wxx3]

We always run one one filter, keeping the other as a backup. That's the point of having two. If one clogs, you can switch to the other underway.

Single and they were designed to work in this way.
The dual function is only when desperate.

 

[newbernbuck]

Thanks everyone, good advice all. Yes the diffuser in one filter was nearly clogged and the other filter diffuser was actually broken off and laying in bowl. Someone got rough on it while installing last time I suspect.
Learning every day..

 

[ranger58sb]

Many of the Mainships were plumbed with a Racor as a secondary filter with the primary being engine mounted on the Perkins. If this is the case than I would re-plumb to only go through one Racor and keep the other plumbed as backup as suggested.

FWIW, just a terminology note...

Many folks consider the off-engine Racor as primary (first in line) and the on-engine fuel filter as the secondary (second in line).

Don't know as that's the "Gospel According to Racor" (or Perkins, or Lehmen, etc.) or not, but it matches the way our engine manual discusses fuel filters.

-Chris

 

[waddenkruiser]

Single and they were designed to work in this way.

The dual function is only when desperate.

We have both engines equipped with 2 secondary filters each which are mounted directly on the engine.
They are served from one fuel header (which is also serving the gen and the heater).
The fuel header gets pre filtered fuel via 2 racors (500), each connected with one tank (starboard / port, both tanks can only be leveled manually via a balance line). Usually both racors are in operation when underway, otherwise we would only suck the fuel from one side ...

Richard, do you see a problem with this? Do they really not work properly if they get "only" 5-7 liter / hour each?
I don't find any minimum flow figures in the racor manual ...


best regards / med venlig hilsen
wadden

 

[Keysdisease]

The whole time I was writing my post I was thinking my terminology was wrong, but I doggedly kept to the logic that the engine mounted filter was primary. Should have looked it up, was lazy.

I stand corrected, the manual is Bible.

FWIW, just a terminology note...

Many folks consider the off-engine Racor as primary (first in line) and the on-engine fuel filter as the secondary (second in line).

Don't know as that's the "Gospel According to Racor" (or Perkins, or Lehmen, etc.) or not, but it matches the way our engine manual discusses fuel filters.

-Chris

 

[ranger58sb]

Not to worry. I, of course, have never had a brain phart in my life.


Everyone believes me about that, right?





-Chris