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Fuel Starvation and The Obscure Ball Check Valve

Feb 26, 2004
21,809
Catalina 34 224 Maple Bay, BC, Canada
On September 20, 2019, I was motoring back from a few enjoyable nights at my favorite local anchorage when I experienced a fuel starvation issue for the first time in my boat. We have sailed Aquavite since 1998. The engine simply sputtered and died, would restart after a few minutes and die again. There were no previous issues, ever.

I replaced the fuel pump. I had corrected the fuel flow from the tank to the primary when we first got the boat. I replaced the primary filter last year. I replaced the secondary filter. When a test sail proved fruitless, I had to go further.

I remembered reading the Racor manual ages ago about a "fuel check valve" that's cleverly hidden at the inlet of the filter housing. It's called a ball check valve, which keeps fuel from emptying from the filter if the tank is below the filter, which makes sense. I undid all the new fuel hoses I'd just put in (!) for the new fuel pump and unscrewed the primary filter and bowl, and then removed the housing.

The filter housing is the Racor 220 / 225 Spin On Series, using the ubiquitous Racor R24 Series filters, installed on most Catalina 34 boats. On the top of the housing is a large plastic screw, identified in the manual’s first page diagram as the “Flow Check Valve” and on page four, it is replacement part list Item 3, part # RK20011, “Check ball valve and plastic cap.”

I unscrewed the check valve plug and O ring and found 33 years of accumulated tiny black particles that kept the ball from rising and allowing fuel to flow. It didn't take much crud at all to stop the ball from working properly. It's a very small chamber about the size of a quarter and the ball is smaller than a dime. There was actually no "bad fuel" issue, just decades of what I would consider to be normal stuff found in any liquid. I cleaned it out, and things are back to working properly.

If you have fuel starvation issues, or anything that reduces your engine RPMs, consider this obscure fuel filter housing ball check valve as part of your diagnostics.

PS The Racor 500 series housings do NOT have check valves in the housing, but the manual says to install a check valve in the inlet of your fuel hoses to the housing if your tank is below the filter.

IMG_20200722_133855 (Small).jpg
 

Ward H

.
Nov 7, 2011
3,076
Catalina 30 Mk II Barnegat, NJ
Thanks Stu. That's the filter I have and never knew there was a check valve in there. Missed it on the manual.
 
Dec 14, 2003
1,292
Hunter 34 Lake of Two Mountains, QC, Can
Good post indeed ! Have had fuel starvation issues twice in the last 2 years even though I totally emptied and cleaned the tank and R24 filters did not look bad. So thanks ! I'll make sure to clean that ball check valve !
 
Jan 4, 2006
3,773
Hunter 310 West Vancouver, B.C.
I remembered reading the Racor manual ages ago about a "fuel check valve" that's cleverly hidden at the inlet of the filter housing
PS The Racor 500 series housings do NOT have check valves in the housing, but the manual says to install a check valve in the inlet of your fuel hoses to the housing if your tank is below the filter.
This becomes a bit of a philosophical conundrum. "Why do you need a check valve before the fuel filter when the fuel tank is lower than the filter" ?

1. The only way the fuel line downstream of the filter can drain back to the fuel tank is to have a leak downstream of the filter. Air is required to replace the fuel as it drains away. No air, no drainage. A check valve does nothing if there is no leak.

2. Now, IF YOU DO HAVE A LEAK downstream of the filter, the operating engine will suck air with the accompanying problems that air causes. Got to fix it right now or forever be plagued with problems.

What has the check valve accomplished here :snooty: ?
 
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Feb 14, 2014
5,552
Hunter 430 Waveland, MS
What has the check valve accomplished here?
:plus::plus:

Clean fuel, no gunk to plug the useless check valve.

If I see air in my Racor 500, then I have the clue for where air leak is.;)
Jim...

PS: Good post so others can remove the ball in their check valve.:pimp:
 
Jan 11, 2014
7,628
Sabre 362 113 Fair Haven, NY
This becomes a bit of a philosophical conundrum. "Why do you need a check valve before the fuel filter when the fuel tank is lower than the filter" ?

1. The only way the fuel line downstream of the filter can drain back to the fuel tank is to have a leak downstream of the filter. Air is required to replace the fuel as it drains away. No air, no drainage. A check valve does nothing if there is no leak.

2. Now, IF YOU DO HAVE A LEAK downstream of the filter, the operating engine will suck air with the accompanying problems that air causes. Got to fix it right now or forever be plagued with problems.

What has the check valve accomplished here :snooty: ?
This model of a Racor filter has a small pump built into the filter to fill the filter after changing it and/or to pump fuel into the system to bleed the lines. Without a check valve fuel could be pumped back into the tank.
 

RoyS

.
Jun 3, 2012
1,118
Hunter 33 Steamboat Wharf, Hull, MA
If your return line from the injectors back to the tank does not go to the tank bottom air can enter there. A check valve can prevent this.
 
Jul 5, 2011
584
Oday 28 Madison, CT
Excellent post, Stu. Much appreciate. Any way one can clean that valve in place if not too filthy or has the whole assembly really got to be pulled out?
 

jviss

.
Feb 5, 2004
4,599
Tartan 3800 Westport, MA
So you guys, @Ralph Johnstone and @JamesG161 think that Racor got it wrong, and the ball check valve is unnecessary? That's amazing, that you have outsmarted a company that absolutely dominates the diesel fuel filter business, and not just for boats, but for trucks, etc. Maybe you should tell them?

Kidding aside, if something seems contradictory to you, perhaps you don't understand it, or have a conceptual problem with it.

Fuel will seek its own level. The tank is vented. If you pump fuel UP to the filter housing without a check valve and then release the vacuum or low pressure that's pulling the fuel up, the fuel will flow back in the line towards the tank until it finds its level in the line matching the level in the tank. A check valve at the filter housing prevent the fuel from flowing back. Simple. It will also prevent the fuel from the filter housing to the injection pump from draining back, too. (It's likely the pump wouldn't work without the check valve, anyway.)

Without this it would take forever to start your engine, if you could start it at all. And you'd no doubt flood your muffler before the thing started.

As @dlochner points out, these housings have an integral pump to facilitate priming of the fuel lines after a filter change.

220/225R Spin- on Series Fuel Filter/Water Separators for Diesel Engines
 
Feb 8, 2014
1,300
Columbia 36 Muskegon
A
This becomes a bit of a philosophical conundrum. "Why do you need a check valve before the fuel filter when the fuel tank is lower than the filter" ?

1. The only way the fuel line downstream of the filter can drain back to the fuel tank is to have a leak downstream of the filter. Air is required to replace the fuel as it drains away. No air, no drainage. A check valve does nothing if there is no leak.

2. Now, IF YOU DO HAVE A LEAK downstream of the filter, the operating engine will suck air with the accompanying problems that air causes. Got to fix it right now or forever be plagued with problems.

What has the check valve accomplished here :snooty: ?
The check valve prevents the fuel from running back when you change the filter. Does nothing while running. Without it you'd have a lot of pumping to do after a filter change. Personally I'd prefer the pumping over having the engine quit at a bad moment.
 

jviss

.
Feb 5, 2004
4,599
Tartan 3800 Westport, MA
@Stu Jackson do you have a vacuum gauge installed? It would be interesting to know the reading when this was happening.
 
Feb 14, 2014
5,552
Hunter 430 Waveland, MS
The check valve prevents the fuel from running back when you change the filter.
Not if, like mine, mounted higher than the injectors and with a vacuum gauge to show performance.
I have 3 spare cartridges aboard, 10 µ , no water ever seen, changed it just once in 5 years.

But...
The Newest Racor 500 maintenance kit does have a ball and seat in it.;)
Jim...

PS: Clean fuel, no gunk, no water, marina fuel has algaecide in it already.:cool:
 
Jan 4, 2006
3,773
Hunter 310 West Vancouver, B.C.
This model of a Racor filter has a small pump built into the filter to fill the filter after changing it and/or to pump fuel into the system to bleed the lines

First of all, the lines downstream of the filter won't drain unless there is a leak to admit air.

Secondly, the small pump WILL fill the filter bowl but WON'T bleed the downstream lines (as far as the LP pump) unless the lines are opened to vent the air.
 
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Jan 4, 2006
3,773
Hunter 310 West Vancouver, B.C.
If your return line from the injectors back to the tank does not go to the tank bottom air can enter there. A check valve can prevent this.
Not really. You have a check valve in the loop at the LP pump (either mechanical or electrical) and I "believe" at the HP pump. Not 100% sure of the HP pump as I'm not familiar with the engine.
 
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Jan 4, 2006
3,773
Hunter 310 West Vancouver, B.C.
Fuel will seek its own level. The tank is vented. If you pump fuel UP to the filter housing without a check valve and then release the vacuum or low pressure that's pulling the fuel up, the fuel will flow back in the line towards the tank until it finds its level in the line matching the level in the tank.
Who let the air in ? (Not to be confused with the Baha Men singing "Who Let the Dogs Out").

The small vacuum that's in the line cannot be released unless air is admitted. At the very least, the LP pump is a good check valve.
 
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