Racor FG500 issue?

[Sailing Drummer]

I always check the bowl on the Racor. I use a flashlight and look all around. I’ve been doing this for as long as I’ve had this boat (this is my first diesel - Yanmar 4JH5E) which is about 11 years. But recently I’ve had reason the actually look at the filter every day. I change the filter every 500 hours as per the recommended service from Yanmar. But I’ve never really looked it except to change it. So now that I’m looking at it I’m seeing what I believe to be very strange.

When I pull it out I see that most of the fuel in the upper portion of the Racor is gone. The bowl is full but that’s all the fuel there. I know there’s some fuel in the filter but not enough to be what’s missing. So I’ve been adding diesel to top it off. I checked the entire housing and there is no fuel leaking. The last few days the motor has run for about 10-12 hours per day. The longest it’s run recently has been about 36 hours. It’s been basically the same each time I check it - the only fuel in there is what’s in the bowl. And I start each run filling the entire housing.

Any ideas what could be causing this? Or this supposed to be how it works?

I don’t always have a connection so if I don’t respond quickly it’s probably that I don’t have any kind of cellular or WiFi.

Thanks
Larry

[NCboatrx]

I would suspect an air leak from either the small O ring that seals the T handle to top lid or the large flat rubber ring that seals the lid to the body. If there are any chips (or corrosion) in the finish of the body where the top flat rubber seats, that must be addressed as well.

[DougR]

Most typically you have a small air leak between the fuel in the tank and the Racor filter. Very small amounts of air are entrained with the fuel and pulled into the Racor. This air flows in with the fuel, down thru the body of the filter and then rises up to the element area where it is trapped. As long as this trapped air doesn’t get too big it won’t cause a problem, and even if some air is pulled thru to the engine it might not cause a problem......it depends on the engine fuel system and the amount of fuel it returns to the tank. It’s also possible that the fuel in the tank is getting air bubbles in it from the return fuel splashing, and this air is being pulled into the system.

Check and reseal all of the fittings and hoses and you will probably fine a small air leak that is causing the problem.

[Sailing Drummer]

A new o-ring and flat rubber ring. That makes sense. The last few filters I’ve gone through were after a day’s run. I had a problem with rust from my tank and that was fouling the filters. Since the filters that got fouled were new, I figured I probably didn’t need the new o ring and gasket.

I’ll also check the fuel line and the connection at the tank to make sure all is tight - all of that was disconnected when I had the fuel polished.

Thanks to both of those answers.

[GordMay]

You have to re-fill the Racor, to the top of the filtre media - not just the bowl.


500FG Turbine Series Instructions ➥ https://www.parker.com/literature/Ra...ine_Series.pdf

Filter Replacement Procedure ➥

https://www.youtube.com/watch?v=XoepJbqXW_0

[Sailing Drummer]

Gord - I do re-fill the entire Racor. That video is a good refresher. Thanks

[goboatingnow]

Of course the clear Racors are not allowed on CE boats

[Sailing Drummer]

Update - I replaced the handle O ring and the large rubber ring for the top. I tightened the clamp for the intake at the Racor, it wasn’t loose but I got about another 1/4 turn on it before I was satisfied it was tight enough but not too tight to distort the clamp. The clamp at the fuel tank was tight. I checked with a paper towel and found no leaks.

This morning the top part was empty. The filter had close to nothing left in it. It took 1/2 gallon of diesel to bring it back up to the top including saturating the filter.

I do have a 3 way valve that I have not checked yet. I will do that tonight after the engine cools down (I forgot to check that last night). If that doesn’t do anything or if the issue doesn’t magically go away I’ll switch over to the other Racor, which might eliminate any issue inside the tank if that one works fine.

Definitely won’t have cellular/WiFi tonight, so I’ll report back some time tomorrow afternoon.

[Sailing Drummer]

New update.

I have not found any air leaks in the entire system. After looking through a variety of online sources one possible and probable cause came up a few times - the check valve in the Racor. This Racor has about 4500 hours use and has never been rebuilt. So my next step will be to rebuild the Racor. Fortunately, it’s summer. And unlike most other boaters here in the Chesapeake, this is the time of year for working on the boat instead of using it! So I’ve added the job of rebuilding it to my growing list of work to be done.