I am having a problem with my rancor fuel filter. After the boat sits for a few days the fuel level goes down to well over half way. I changed filter recently. Any ideas.
Rancor fuel filter
- Thread starter rbenyoung
- Start date
Air leak. Could be in bowl gasket or any connection between the filter and the engine. Most likely the bowl gasket since that was last worked. Hope ya find it.
Rancor can be a bitter pill.
Rancor can be a bitter pill.
Can you start your engine and run after all the air is bled out?
Since this did not happen before you changed the RACOR filter cartridge, are you sure it was the right filter cartridge for your Racor 500?
Jim...
Since this did not happen before you changed the RACOR filter cartridge, are you sure it was the right filter cartridge for your Racor 500?
Jim...
The gaskets in those things often swell after being exposed to fuel for a while. When you change the filter, you usually need to put in new gaskets/o-rings because the old ones will not fit anymore. If you let the old gaskets sit out in open air for a week or two, they often come back to normal size. I always carry a spare o-ring/gasket kit on the boat, in case I need to open it up while at sea.
Those things have a pretty good vacuum rating, but they often need to be surprisingly tight in order to achieve it. The last one that I got new from the factory was so tight, that I could not get it apart. I asked the guy at the shop where I bought it if he had any tricks for getting it apart, he returned from the back room with a damaged filter, but the housing was still in good shape. It was that tight.
I often put a THIN film of Dow Corning 111 lubricant on my o-rings before reassembly. It seems to make everything more user friendly.
I did have one off-brand filter housing that had a hairline crack at a fitting boss. I could not locate the source of that air leak until I put the whole filter assembly into a bucket of water & watched for the bubbles to start & stop when different parts of the assembly were submerged. I have never had that issue on a genuine Racor brand filter housing. In fact, that one time was the only time I have ever seen that issue. Usually when they leak, it's at a gasket.
Those things have a pretty good vacuum rating, but they often need to be surprisingly tight in order to achieve it. The last one that I got new from the factory was so tight, that I could not get it apart. I asked the guy at the shop where I bought it if he had any tricks for getting it apart, he returned from the back room with a damaged filter, but the housing was still in good shape. It was that tight.
I often put a THIN film of Dow Corning 111 lubricant on my o-rings before reassembly. It seems to make everything more user friendly.
I did have one off-brand filter housing that had a hairline crack at a fitting boss. I could not locate the source of that air leak until I put the whole filter assembly into a bucket of water & watched for the bubbles to start & stop when different parts of the assembly were submerged. I have never had that issue on a genuine Racor brand filter housing. In fact, that one time was the only time I have ever seen that issue. Usually when they leak, it's at a gasket.
I’ve heard several cases where the powder coat in the gasket groove starts flaking preventing a seal.
I thought a Rancor was the beast in Jaba the Hutt’s castle. With rancor being what exists between me and my brother.
Les
I thought a Rancor was the beast in Jaba the Hutt’s castle. With rancor being what exists between me and my brother.
Les
If the air occures after sitting a few days then I'm thinking that it was in there all the time. If it was an air leak then the motor would let you know by stalling. Thinking it is sucking the air bubble into the supply line but not enough to move to the engine and cause a problem. On shutdown it move slowly back the the top of the fuel circuit (filter??). This is all based on the assumption that the fuel filter is at the high spot in the fuel line like it is supposed to be and that engine is not drawing fuel fast enough to suck the air bubble into the injection pump.
Someone recently posted that the check valve in the housing got stuck. A friend also reported that his vent screw at the top of the housing had come loose, introducing air.
These are in addition to previous comments, which are spot on.
These are in addition to previous comments, which are spot on.
That's what I thought. Hence the question about what's going on at the bottom. But nothing going on there he says.
Which makes me think Kloudie got it right off. The fuel is being drained out of the bowl by gravity to the tank, coming up through the bottom of the centrifuge. This can only occur if a vent (air leak) is allowing it to do so. Most likely a leak at the top of the cylinder; the top gasket.
Or maybe he forgot to put the little red o-ring back in under the handle, or it fell out unnoticed.
New gaskets and o-rings come with the filters. They're hiding in the bottom of the wrapper.
Last edited:
I replaced both Orings when I rplaced the the filter. This makes sense though. I can check both orings latter today.