Reply
 
Thread Tools Display Modes
 
Old 04-11-2016, 11:04 AM   #1
Veteran Member
 
newbernbuck's Avatar
 
City: New Bern, NC
Country: United States
Vessel Name: HALLIN
Vessel Model: Mainship 34 MK1 1982
Join Date: Feb 2016
Posts: 38
question re: dual racor 500's on Mainship 34

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
__________________
Advertisement

newbernbuck is offline   Reply With Quote
Old 04-11-2016, 11:19 AM   #2
Master and Commander
 
markpierce's Avatar
 
City: Vallejo CA
Country: USA
Vessel Name: Carquinez Coot
Vessel Model: 2011 Seahorse Marine Coot hull #6
Join Date: Sep 2010
Posts: 10,254
I use one of my two Racors at a time.
__________________

__________________
Kar-KEEN-ez Koot
markpierce is offline   Reply With Quote
Old 04-11-2016, 11:21 AM   #3
Guru
 
dhays's Avatar
 
City: Gig Harbor
Country: United States
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 5,080
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.
__________________
Regards,

Dave
SPOT page
dhays is offline   Reply With Quote
Old 04-11-2016, 11:23 AM   #4
Guru
 
Drake's Avatar
 
City: Seabrook, Texas
Country: Independent Republic of Texas
Vessel Name: Small World
Vessel Model: Defever 50
Join Date: Sep 2014
Posts: 506
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.
Drake is online now   Reply With Quote
Old 04-11-2016, 11:26 AM   #5
Senior Member
 
obthomas's Avatar
 
City: Seabrook Texas
Country: USA
Vessel Name: TheVenture
Vessel Model: 1985 Bestway Labelle Sundeck 40ft
Join Date: May 2013
Posts: 462
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.
obthomas is offline   Reply With Quote
Old 04-11-2016, 11:47 AM   #6
Guru
 
Ski in NC's Avatar
 
City: Wilmington, NC
Country: USA
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 3,882
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.
Ski in NC is offline   Reply With Quote
Old 04-11-2016, 11:47 AM   #7
Veteran Member
 
Busterbrown's Avatar
 
City: Corona
Country: USA
Vessel Name: SCRAMBLER
Vessel Model: 1974 Grand Banks 32 #536
Join Date: Jul 2013
Posts: 55
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
Busterbrown is offline   Reply With Quote
Old 04-11-2016, 12:04 PM   #8
Senior Member
 
Keysdisease's Avatar
 
City: South Florida
Country: USA
Join Date: Sep 2014
Posts: 460
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.

Attached Images
 
Keysdisease is offline   Reply With Quote
Old 04-11-2016, 12:48 PM   #9
Dauntless Award
 
Wxx3's Avatar
 
City: New York, NY
Country: USA
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,312
Quote:
Originally Posted by Drake View Post
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.
__________________
M/Y Dauntless, New York
a Kadey Krogen 42 Currently https://share.delorme.com/dauntless
Blog: https://dauntlessatsea.com
Find us: https://share.delorme.com/dauntless
Wxx3 is offline   Reply With Quote
Old 04-11-2016, 02:04 PM   #10
Veteran Member
 
newbernbuck's Avatar
 
City: New Bern, NC
Country: United States
Vessel Name: HALLIN
Vessel Model: Mainship 34 MK1 1982
Join Date: Feb 2016
Posts: 38
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..
newbernbuck is offline   Reply With Quote
Old 04-11-2016, 03:01 PM   #11
Guru
 
ranger42c's Avatar
 
City: Maryland
Country: USA
Vessel Model: 42' Sportfish
Join Date: Aug 2013
Posts: 3,156
Quote:
Originally Posted by Keysdisease View Post
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
__________________
South River, Chesapeake Bay
ranger42c is offline   Reply With Quote
Old 04-12-2016, 05:34 AM   #12
Senior Member
 
waddenkruiser's Avatar
 
City: Southern Baltic
Country: Europe
Vessel Name: Sømarken
Vessel Model: AMS 40'
Join Date: Jul 2012
Posts: 183
question re: dual racor 500's on Mainship 34

Quote:
Originally Posted by Wxx3 View Post
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
__________________
best regards / med venlig hilsen
Wadden
waddenkruiser is offline   Reply With Quote
Old 04-12-2016, 06:13 AM   #13
Senior Member
 
Keysdisease's Avatar
 
City: South Florida
Country: USA
Join Date: Sep 2014
Posts: 460
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.



Quote:
Originally Posted by ranger42c View Post
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
Keysdisease is offline   Reply With Quote
Old 04-12-2016, 07:17 AM   #14
Guru
 
ranger42c's Avatar
 
City: Maryland
Country: USA
Vessel Model: 42' Sportfish
Join Date: Aug 2013
Posts: 3,156
Not to worry. I, of course, have never had a brain phart in my life.


Everyone believes me about that, right?





-Chris
__________________

__________________
South River, Chesapeake Bay
ranger42c is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 05:17 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012