Fuel Starvation and The Obscure Check Ball Valve

Stu Jackson · August 09, 2020, 10:07:43 AM

This article is for housings for Racor 24 Series filters. These housings have the built-in heck valves. For their other filter housings, Racor recommends check valves in the fuel system to avoid fuel return to tanks that empties the filters.

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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.

UPDATE - September 2022 - Also make sure you clean the opening BELOW the ball itself where the fuel drops down into the filter. I experienced yet another starvation issue due to this section being clogged, too.

Jon W · August 09, 2020, 12:39:50 PM

Great info Stu, thanks for posting.

Oldlaxer1 · August 09, 2020, 02:02:45 PM

You could have told us this morning 😀. I'll be checking mine tomorrow. Thanks for the info.

KWKloeber · August 09, 2020, 09:54:15 PM

Quote

obscure fuel filter housing ball check valve

Stu that is such helpful info. I had no idea but I'm passing that on.
I hope you don't mind - I added your blurb to the wiki "fuel" page.

Jim Lucas · August 10, 2020, 10:41:48 AM

Thanks Stu,
Such an easy service item to know about and check... I'll take a look at mine at my next engine check over.

Stu Jackson · August 10, 2020, 03:10:35 PM

Point should be made that Mark I and I 1/2 boats have their filters under the head sink, which is why I had to remove the filter to remove the housing to do this.

IIRC, the fuel filter on Mark II boats is under the aft berth and the ball check valve can be accessed easily.

Stu Jackson · August 10, 2020, 03:11:31 PM

Quote from: KWKloeber on August 09, 2020, 09:54:15 PM
Quote

obscure fuel filter housing ball check valve

Stu that is such helpful info. I had no idea but I'm passing that on.
I hope you don't mind - I added your blurb to the wiki "fuel" page.

Of course, pass it on. I've noted it on CF, will do so on sbo.

Thanks for posting to the wiki.

I added it to Critical Upgrades, too.

Breakin Away · August 10, 2020, 03:12:11 PM

This is helpful and timely, as I was just recently wondering if debris buildup in this check valve could cause fuel starvation that is incorrectly attributed to a plugged fuel filter. I haven't experienced such an issue (yet) this season, but every couple of years I see it, and had immediately replaced my Racor R15P when I might not have needed to.

But let me add that there may be a second check valve in the spin-on filter apparatus that may need periodic attention: The priming pump. It looks to me like the pump is a typical plunger-with-a-flapper that forces unidirectional flow (just like a check valve does) and also presents a flow restriction that could be clogged by debris on top of the plunger (although perhaps the ball in the check valve acts as a "prefilter" for the plunger). I know from experience that whenever I let the priming pump sit unused for a couple of months, it is initially difficult to operate, then a little debris gets "squeezed out" (and drops into the bowl) after which the pump is suddenly much easier to operate. I immediately drain the bowl of this debris to keep it from plugging up my (expensive, overpriced) Racor filter.

By the way, I also recently raised my Racor filter housing by 2" because Catalina had mounted it so low in the transmission sump (on my MkII boat) that it was impossible to get a decent sized container under the petcock. I recommend that MkII owners do this if needed. It might create enough space underneath to put something larger than my R15 filter element in there.

The access to the Racor in the MkII's sounds like it is a little better than the earlier boats, but it's still really crowded with the transmission/throttle cables and associated mounting plate.

Noah · August 10, 2020, 03:27:57 PM

My Racor 500 turbine filter is under the head sink but is also
Lower than the fuel tank so no check
Valve needed.

Stu Jackson · August 10, 2020, 03:59:52 PM

Quote from: Breakin Away on August 10, 2020, 03:12:11 PM
>>>>>>>>>>>>>>>>>>

I know from experience that whenever I let the priming pump sit unused for a couple of months, it is initially difficult to operate, then a little debris gets "squeezed out" (and drops into the bowl) after which the pump is suddenly much easier to operate. I immediately drain the bowl of this debris to keep it from plugging up my (expensive, overpriced) Racor filter.

>>>>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>>>>>>>>>

Glad to help.

Can you share with us why you use your manual pump on the filter housing? In the 23 years I have owned our boat, I have used it once, 22 years ago (!) and my fingers are still sore.

I always use the fuel pump.

It could well be that your fuel pump doesn't work with the engine off without operating the glow plugs unnecessarily. I wrote that up as an unforeseen consequence of the change in wiring after the M25 engines in Critical Upgrades.

Breakin Away · August 10, 2020, 04:14:10 PM

It's all about keeping air from getting to the banjo washers.

Whenever I replace the Racor filter I pre-fill it as much as I can, but cannot fill it all the way because I need to tip it over a little to get it under the aft berth/transmission sump on my MkII. Then I remove the pinch valve from my incoming fuel hose (easier/more effective than the valve on top of the tank), open the vent screw, and operate the Racor priming pump until fuel bleeds out the vent screw. After that I close the vent screw and operate the lift pump for 30-60 seconds or so (10 sec at a time with resting period in between to save the glow plugs), then start up the motor to test for 20 minutes (since getting an air lock while leaving your slip can ruin your day).

Going forward, I will operate the Racor priming pump monthly and inspect the bowl for any debris. I suspect that the pulsing from the manual pump may also cleanse the check valve of any debris that has built up there.

You may find that actuating the pump more often than once every 22 years keeps it operating smoothly and goes easier on your fingers. But it is much more accessible on the MkII boats.

Ron Hill · August 11, 2020, 09:22:24 AM

Guys & Stu : The M35BC and the M25XPB are not self bleeding fuel systems and you do not have a bleed valve.
It is best to get all of the air out of the filters after installing them.

A thought

KWKloeber · August 11, 2020, 04:33:12 PM

Ron

I don't have an xpb but from my buddy who used to have one, I thought it was continuously bled thru the banjo and fuel return line? Have I lost my mind (for the "nth" time?)

If it becomes necessary to bleed air from the engine fuel
system, tum the panel key ON and interrnitently (5 - 10
seconds). Activate the preheat circuit This activates the fuel
which draws fuel into the engine fuel system and drives air
out via the fuel return.

Stu Jackson · August 12, 2020, 10:56:09 AM

Quote from: KWKloeber on August 11, 2020, 04:33:12 PM

If it becomes necessary to bleed air from the engine fuel
system, tum the panel key ON and interrnitently (5 - 10
seconds). Activate the preheat circuit This activates the fuel
which draws fuel into the engine fuel system and drives air
out via the fuel return.

Ken, did you mean?

This activates the fuel PUMP which draws fuel into...

Ron Hill · August 12, 2020, 02:16:18 PM

Ken & Stu : I believe that you are correct on the fuel pump bleeding.
FYI, I took the new wiring harness off my new M25XPB engine, installed a single pole oil sender and wired the glow plugs direct into the spring loaded pole of the key switch - So the engine matches the boats 1988 engine wiring - not the new goofy fuel pump/glow plug wiring!!

Works like a charm and MUCH simpler!!

A thought