Racor 500 series fuel filter and fuel level therein

[Laser fun]

Hello. First time poster and long time reader. After water contamination problem on ICW we're back in the slip. We've been running the Yanmar 3gm30f daily to ensure water out of system.

Now it has come up that we are adding 1-2 oz of fuel to the Racor after every 30' engine run to bring the fuel level in the filer housing up to the top of the plastic top of the filter. (About 1/8th inch below rim of Racor housing)

Some are saying this can be normal and some are saying not! Any input appreciated.

Original reason for all the engine test runs was to remove water and air from the fuel line we replaced. Most if not all replaced clamps on the fuel line has been checked and tightened ... Again. The fuel tank pressure relief value has been checked and is free and clear to make sure there was't a vaccum.

Thanks.


Sent from my iPad using Cruisers Sailing Forum

[svHyLyte]

Originally Posted by Laser fun

Hello. First time poster and long time reader. After water contamination problem on ICW we're back in the slip. We've been running the Yanmar 3gm30f daily to ensure water out of system.

Now it has come up that we are adding 1-2 oz of fuel to the Racor after every 30' engine run to bring the fuel level in the filer housing up to the top of the plastic top of the filter. (About 1/8th inch below rim of Racor housing)

Some are saying this can be normal and some are saying not! Any input appreciated.

Original reason for all the engine test runs was to remove water and air from the fuel line we replaced. Most if not all replaced clamps on the fuel line has been checked and tightened ... Again. The fuel tank pressure relief value has been checked and is free and clear to make sure there was't a vaccum.

Thanks.


Sent from my iPad using Cruisers Sailing Forum

There should not be any "air" in the FG500 Filter Housing in normal operation. Assuming the O-Ring at the top of the filter canister is properly seated, loosen the locking screw on the top of the filter assembly and manually pump your lift pump until fuel flows out, around the screw, and then lock it down. If air appears again, you have a leak in either the fuel line seals to the filter, at the lift pump; or, at the O-Ring.

[David M]

Put a little pressure in the system and look for diesel bleeding out.

[donradcliffe]

I've been on boats where the level in the Racor was down on the order of an inch from the top when I went to replace the filter. If the engine is running good I'd not worry about it.

[Rough Magic]

Mine always ran an inch or so from the top, never had a problem. If there was an air leak, it didn't cause any issues. I changed filters every 100 hours.

[Cheechako]

Originally Posted by svHyLyte

There should not be any "air" in the FG500 Filter Housing in normal operation. Assuming the O-Ring at the top of the filter canister is properly seated, loosen the locking screw on the top of the filter assembly and manually pump your lift pump until fuel flows out, around the screw, and then lock it down. If air appears again, you have a leak in either the fuel line seals to the filter, at the lift pump; or, at the O-Ring.

With the screw out you have no vacuum to draw fuel into the filter......right? To fill it up you would need a pump prior to the Fuel filter. Most are installed before the lift pump that I have seen.
I always fill the filter to the top manually prior to closing . But as mentioned, I have seen them below the top many times and running fine.

My question for the OP is: did you find the problem that got water in your system?

[Shenandoah]

The air in the top of the filter is from somewhere "upstream" in the fuel system. The design of the filter housing has the input and output low enough that it doesn't get air to the injection pump in normal operation. However, the source of air should be located as it could get worse and cause a problem. Simply put, you don't want air in a diesel fuel system. Among other problems, this makes the lift pump work harder. Replace the small o-ring on the T-handle as well as the bigger one on the lid. Get a vacuum gauge (Mity-Vac or equivalent) and test each section of the lines upstream until you find where it is getting air in. I once found a crack in a fitting that caused a truck to stop. A $2 part left a fellow on the side of the road. Don't wait until it gets worse when you are in a dangerous situation.

[Terra Nova]

There is an air leak in your system. Find it, yourself, or hire a pro.

If there is a fuel shutoff valve right at the tank, close that and pressurize the line to the filter by connecting a reservoir to its other end, held higher than the shutoff valve. For every 2' of height, you will get ~ 1 psi. Temporarily extend the hose, if necessary. Be certain the hose is full of fuel. Raising it a few feet should be sufficient to cause fuel to wet the leak.

Or you can empty the hose, blow in the filter end, and see if bubbles form at soaped connections. Check also for damage to hose. Replace old/damaged hoses with one continuous run from tank to filter.

Never heard of a fuel tank pressure relief valve. It should at all times be vented to atmosphere using 5/8" fuel hose.

[Snore]

+1 on air leak. Assuming you cannot see an obvious leak---

I have always had good luck "papering" the engine. To do this, bleed the system and get it running. Immediately turn it off and place paper towels under the fuel line and filters. Check back the next day. The towel under the leak will have a small stain.


Sent from my iPhone- please forgive autocorrect errors.

[Triumphant]

I have a Racor 500 installed before the mechanical lift pump and the fuel level is always at the top when I open it up to change the filter.

The only time it was not up to the top was when I had a problem with the (28 year old) lift pump. Swapped the pump out and the problem went away

[svthreecheers]

Originally Posted by Laser fun

Hello. First time poster and long time reader. After water contamination problem on ICW we're back in the slip. We've been running the Yanmar 3gm30f daily to ensure water out of system.

Now it has come up that we are adding 1-2 oz of fuel to the Racor after every 30' engine run to bring the fuel level in the filer housing up to the top of the plastic top of the filter. (About 1/8th inch below rim of Racor housing)

Some are saying this can be normal and some are saying not! Any input appreciated.

Original reason for all the engine test runs was to remove water and air from the fuel line we replaced. Most if not all replaced clamps on the fuel line has been checked and tightened ... Again. The fuel tank pressure relief value has been checked and is free and clear to make sure there was't a vaccum.

Thanks.


Sent from my iPad using Cruisers Sailing Forum

The Racor filters 5oo/900/1000 series are never all the way full when the engine
is running. Created by the vacuum from the fuel transfer pump on the engine.
Your racor filter should be installed before the transfer pump in the
Vacuum side of the fuel system
I never heard of a pressure relief valve on the fuel tank, we usually
install a vent as big as possible to prevent spills when you fill up.
Installing a vacuum gauge on the filter is a good idea to check for
leaks and when to change the filter cartridge.
So don't worry!
Siggi

[jongleur]

Originally Posted by svthreecheers

filter should be installed before the transfer pump in the Vacuum side of the fuel system

Why??

(I added a question mark to increase my
response to 5 characters or more, so it would
post. Now it's long enough to post, because
if it were only 4 characters, like "Why?" it
wouldn't post, so now it will. I'm so relieved
that it's long enough to post now. Carry on.)

[hamburking]

I had the previous model, racor 200, and it was always filled totally to the top. The filter was lower than the fuel tank. I wonder if you should compare the level of the fuel in the filter to the level of fuel in the tank...what I mean is, gravity feed or fuel pump? If its gravity, it can't go higher than the level in the tank.

Its good that you are on top of this. Better to figure it out at the dock than on a rough passage.

[svthreecheers]

Originally Posted by hamburking

I had the previous model, racor 200, and it was always filled totally to the top. The filter was lower than the fuel tank. I wonder if you should compare the level of the fuel in the filter to the level of fuel in the tank...what I mean is, gravity feed or fuel pump? If its gravity, it can't go higher than the level in the tank.

Its good that you are on top of this. Better to figure it out at the dock than on a rough passage.

Hello hamburking
The Racor 200 is not a turbine filter, I believe it is a spin on cartridge wich works
different than the 500/900/1000 system.
If the filter and the engine is below the fuel tank than you don't have a vaccum line anymore
You have a gravity fed system under pressure all the way.
Cheers
Siggi

[Rustic Charm]

Originally Posted by jongleur

Why??

(I added a question mark to increase my
response to 5 characters or more, so it would
post. Now it's long enough to post, because
if it were only 4 characters, like "Why?" it
wouldn't post, so now it will. I'm so relieved
that it's long enough to post now. Carry on.)

It helps to protect the pump that way.