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06-20-2017, 10:04 PM
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#21
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Senior Member
City: Woodbridge UK
Vessel Name: MV Content
Vessel Model: Fellows & Stewart 58' Pilothouse Cutter
Join Date: Dec 2013
Posts: 116
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Thank you all for your valued input. I've distilled all of your kind advice, and now have a day tank with:
- Racor 500 with 10mic filter on the inlet, with Walbro 40gph pump sucking the juice
- 1 x Racor 900 for each engine, with 2Mic filters, gravity-fed from the Day tank
- secondary filters on each engine with 2Mic again.
Thanks again!
Eamonn
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07-08-2017, 12:19 AM
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#22
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Senior Member
City: Woodbridge UK
Vessel Name: MV Content
Vessel Model: Fellows & Stewart 58' Pilothouse Cutter
Join Date: Dec 2013
Posts: 116
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So here's an update, after about 300 miles with the new tank. It works very well, and the comfort of knowing that the engines are completely isolated from the crud in the tanks is very satisfying.
However, something is not quite right. The engines don't start up first turn, like they used to. With the throttle on minimum (previous setting), they will crank for 7-8 secs before firing. If I raise the throttle a notch, it's much quicker.
Im looking at two areas:
- Because of availability, we had to use 1/2" hose from the day tank to the final Racors, and 5/16th from there to the lift pump. Could the mix of hose be causing a problem?
- the day tank sits lower than the main tanks, with the bottom of the tank level with the final Racors. Could this be the cause?
There is no sign of a leak anywhere in the system.
Suggestions appreciated.
Thanks!
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07-08-2017, 06:14 AM
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#23
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,147
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The fuel could be draining back further to a now lower tank?
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07-08-2017, 06:56 AM
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#24
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Technical Guru
City: Wilmington, NC
Vessel Name: Louisa
Vessel Model: Custom Built 38
Join Date: Jan 2014
Posts: 6,194
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Make sure the Racors don't have a lot of air in them, fuel level inside should be within an inch of the top.
Also, how are return lines from engines run back to the tank? Some engines like the return to actually be a dip tube to prevent air from backing into system on shutdown.
The size of the hose should not matter much, but can trap and hold air in high spots. Flow rate is not fast enough to wash the air through.
What engines are these?
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07-08-2017, 06:59 AM
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#25
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Guru
City: Carefree, Arizona
Vessel Name: sunchaser V
Vessel Model: DeFever 48 (sold)
Join Date: Apr 2008
Posts: 10,185
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Content
Two areas to contemplate:
Air in system resulting from all new plumbing. Did you use Rectorseal 5 or similar on all new fittings? Air could possibly lead to drain back as PSN suggests
Secondly, you've added to the suction head, maybe too much for the lift pumps. Smaller lines as you note and 2 microns in the Racors.
Are the Ivecos electronic? How long would it take for them to start if they sat for a month? Look for my AIS, love to see your boat, it sounds marvelous.
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07-08-2017, 07:07 AM
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#26
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Guru
City: kemah
Join Date: May 2015
Posts: 1,135
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Quote:
Originally Posted by FF
"Also, in my foggy mind I seem to recall that a Racor is better utilized under a vacuum than with a pump feeding it."
Every filter does better having fuel sucked thru as the pump can chop up and mix the water or goop in the fuel making it harder to filter.
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But isnt every primary filter on diesels positioned post pump?
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07-08-2017, 07:13 AM
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#27
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Guru
City: kemah
Join Date: May 2015
Posts: 1,135
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If the injector pump itself loses pressure it can take a while to fire. Cracking the throttle open a bit allows more air flow too, so maybe check the air filter? Just a couple of thoughts.
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07-08-2017, 07:27 AM
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#28
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Senior Member
City: LAFAYETTE,LA
Vessel Name: Relenti
Vessel Model: Atlantic 30, 1983
Join Date: Mar 2015
Posts: 451
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Maybe install an anti-siphon valve between day tank and filters?
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07-08-2017, 08:03 AM
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#29
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Guru
City: Ft Pierce
Vessel Name: Sold
Vessel Model: Was an Albin/PSN 40
Join Date: Oct 2011
Posts: 28,147
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The anti siphon valve on my tank doesnt seem to work well enough to keep things from draining back or pulling air into the system.
Once the fuel level in my starboard tank gets low, every once and awhile I have a low power or stalling issue unless I bleed to the fuel injection pump.
Summer project to chase that bad boy.
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07-08-2017, 08:14 AM
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#30
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Guru
City: Miami
Join Date: Jul 2013
Posts: 800
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Do you have a vacuum gauge on the racor between the day tank and the lift pump to measure what your lift pump is seeing pressure wise? Most engine manufacturers spec 30 micron primaries for a reason. Our lift pump is 3' above the outlet valve on our day tank and our racor primary filters so we normally see -1 psi on the gauge underway. Although we filter at 10 micron going into the day tank we filter at 30 going to the lift pump. Here is a 6 month old 30 micron primary. and here is the 10 micron daytank filter when the vacuum just started to build. Guesstimate of at least 3k gallons of use.
__________________
Via iOS.
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07-08-2017, 08:24 AM
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#31
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Guru
Join Date: Oct 2007
Posts: 22,553
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"Cracking the throttle open a bit allows more air flow too, so maybe check the air filter? Just a couple of thoughts."
There is no throttle plate to open on a diesel engine.
The air is wide open and the power / RPM is set by the throttle lever allowing more or less fuel injection.
"But isnt every primary filter on diesels positioned post pump?"
Usually , that is why caution must be exercised with the use of an emulsifier additive.
A set of secondary filters Fram , Raycor, whatever does a better job when fuel is sucked thru them before feeding the engine.
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07-08-2017, 01:55 PM
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#32
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Senior Member
City: Woodbridge UK
Vessel Name: MV Content
Vessel Model: Fellows & Stewart 58' Pilothouse Cutter
Join Date: Dec 2013
Posts: 116
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Thank you all for your suggestions.
Ski: I'll check the air when I dock in Port Townsend shortly....good call. I have a loop on the return hoses, so that should not be the cause. The engines are Iveco 150, mechanical lift pump.
Sunchaser: not sure which one, but I've got sealant on all joints. In the end, I used 10mic filters on the Racors between the day tank and engine. If I don't find air in there, I'll switch to 30mic. Good idea.
Cafesport: I've got a vacuum gauge, aim to fit it today. Thanks for that!
I'll report back
Cheers, Eamonn.
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07-08-2017, 06:22 PM
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#33
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Dauntless Award
City: Wrangell, Alaska
Vessel Name: Dauntless
Vessel Model: Kadey Krogen 42 - 148
Join Date: Jan 2013
Posts: 2,820
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This is why less is more.
You're engine was happy.
But you weren't.
Now, your happy.
And your engine?
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07-12-2017, 02:48 PM
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#34
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Senior Member
City: Woodbridge UK
Vessel Name: MV Content
Vessel Model: Fellows & Stewart 58' Pilothouse Cutter
Join Date: Dec 2013
Posts: 116
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Well, we took a few things apart, and found a badly-fitted pickup tube in the day tank. Looks like non-diesel tubing, and it had expanded with the heat. That explained the port engine issue. We also found Some grit under the lid on the starboard final Racor (that one was my fault)
I got some great help from Shawn, engineer on a big tug in Neah Bay - put us in good shape for the start of our trip down the west coast.
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07-12-2017, 04:39 PM
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#35
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Guru
City: St Augustine,Fl
Join Date: Sep 2009
Posts: 3,798
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Glad it worked out, MV Content! Purdy boat you have there!
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