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Gascolator servicing intervals

00Dan

Well Known Member
For reasons known only to him and God the builder of my RV-4 placed a gascolator in the forward tunnel in front of the battery and rigged a remote handle for actuating the drain. This, as can be seen in the picture, was clearly not done with serviceability in mind.

My question is, before I go to the trouble of disassembling a rudder pedal to try and unbolt this thing, how often is gascolator service actually required? If it’s not leaking and it drains clean, is there anything to do?
 

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I look inside mine once a year for rust, to clean the filter, etc. If I was you I’d relocate it somewhere more accessible.
 
OUCH...

The gascolator is serviced at every annual/condition inspection or when there's any reason to believe it could contain an extra-ordinary amount of ****. Have you thought about relocating it? A little inconvenience now could save a lot later.
danny
 
Maybe replace with a filter

I too have a gascolator that's not easy to access (I though it would be when I installed it but didn't turn out that way). Been contemplating taking it out and putting filters on each side in the wing root. Google site:vansairforce.net gascolator vs filter and you'll find some compelling arguments for doing that.
 
For reasons known only to him and God the builder of my RV-4 placed a gascolator in the forward tunnel in front of the battery and rigged a remote handle for actuating the drain. This, as can be seen in the picture, was clearly not done with serviceability in mind.

My question is, before I go to the trouble of disassembling a rudder pedal to try and unbolt this thing, how often is gascolator service actually required? If it’s not leaking and it drains clean, is there anything to do?

Is it possible to disconnect the fuel lines, and just remove the gascolator and service it out of the plane?
 
That thing with the plumbing doesn't look like any gascolator I've seen. What is it?

Dave

Top view doesn’t show it but it has a bowl and a drain coming out the bottom through a hole in the skin. If it’s not actually a gascolator I have no idea what it is.

Is it possible to disconnect the fuel lines, and just remove the gascolator and service it out of the plane?

It’s possible but requires moving the left rudder pedal out of the way due to how it’s bolted onto the side wall of the tunnel. It’s enough labor to make me explore what to do with it before I get in there.
 
I would be in favor of removing it (with maybe a home-made tool) and giving it the float test (in the nearest body of water). And then installing an inline filter or two in an easily serviceable location. If you can’t get it out, but can remove the AN fittings on each end, you could just make a new fuel line, or get a flex line, and bypass it - plus install the inline filter(s). Leave it there if it’s too difficult to remove and call it……. ballast for W&B purposes…….
 
Gascolator......

That thing with the plumbing doesn't look like any gascolator I've seen. What is it?Dave

This is why our airplanes are called Custom Built. This is a Cessna gascolator (Google Cessna Gascolator if you want to see one out of the airplane) with the idea of the pilot being able to drain it by pulling a lever in the engine compartment. That way you didn't have to get down on your knees to drain the thing. But: what is coming out of there if you are draining it on to the tarmac? The other reason for using this is keeping the gascolator away from the firewall in case you happen to get the firewall too close to some dirt in an unplanned landing. It is more protected and less likely to part company with the airplane.

I would suggest either leaving it there and replumbing lines to a new, easier-to-access gascolator or taking it out completely (the "float test":D:D) There is one for sale on ebay for $387 which might make you more inclined to take it out....:p The location for the gascolator on the original plans makes it very accessible. I look at everything else on the belly while I am under there draining the bowl of the gascolator. I also look at what is coming out of that filtered fuel. I have found water once. Usually it is amorphous gradeau (unidentifiable junk) but I have found things that have missed the finger screens and tank sumps: occasional red plastic from the funnel I use to fuel (in the Cub).

Inline filters vs gascolator: The gascolator bowl should be the lowest part of the fuel system which is a great place for water to collect. Inline filters will not pull water out of the system. Should you get that out tapping the quickdrains in the tanks? One would think but that is still not the lowest part of the fuel system, especially in the -A types....which yours is not. Can the fuel be filtered too much? I think not..... Gascolators are also easier to service (see what has been filtered out) than inline filters.

IMHO..
 
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A gascolator is definitely not the lowest part of my fuel system (RV6 TD, Andair gascolator on the firewall). In my case, it filters the fuel - nothing more. And I’ve never seen anything in the gascolator bowl. I sump the tanks before every flight, and that is the lowest point in my fuel system. Of course, if I want to sump my gascolator on preflight, I need to get to the cockpit, energize the battery, turn on the electric boost pump, then head around the nose to the right side of the aft cowl to sump the gascolator drain - being rewarded with a shower of 100LL. I don’t know if there’s water in there, but it tastes the same. That’s the first system I’ll replace when I do my first condition inspection after phase one, later this year.

If you have an -A model, it’s probably a different story. You may actually have a low point, depending on where your gascolator is located. In that case, a gascolator installed according to Vans instructions should capture water. For me, the fuel tank quick drain is key for draining out any water. I’ve used inline filters on 4 of my 6 RV’s. My first one (RV6) had a gascolator, and so does my current (and last) one because that is the way it was when I bought the used kit. I will be changing that.
 
If you decide to move or change it, I highly recommend the Aerolab Flush Mounted Filter Gascolator found at Flyboyaccessories.com. I retrofit this very late in my RV4 build and love it. Super simple to check or service from outside the airplane. Quality seems excellent. Not sponsored, just satisfied. Easy enough to check it often if desired.
 
A couple of things to ponder:

If it is a Cessna Fuel Filter Bowl (and it looks very much like it is) these can suffer from corrosion in the bottom of the bowl when water collects there. It is therefore very worthwile removing the bowl at each inspection and checking it. While you might not get much water from your tank drain points, this doesn't always mean you will not get water in your gascolator. Naturally there are always exceptions - both ways. Leaving this in place and not checking it is asking for trouble.

Anytime something is difficult to access it becomes difficult to maintain and therefore tends to be ignored. Your fuel system is pretty critical to your ongoing enjoyment of flight and not maintaining this regularly is... yeah... asking for trouble. While it will be a pain to move this to the forward side of the firewall it would at least be much more accessible and therefore more regularly inspected. If this is not an option for you due to installation problems on the forward side of the firewall then I would highly recommend the AEROLAB gascolator as a viable option for your installation. This unit could be mounted in the belly skin under the current gascolator location and best of all it is very easy to maintain externally - so no fuel being lost inside the cockpit area. Win - win - win!
 
I will also say it looks like a Cessna gascolator. I would remove it. They were made for gravity (very low pressure... no fuel pump) applications. On an RV, the electric fuel pump can over power the aged seal around the shaft on the top that the pull cord is attached to, and makes a big fuel leak.

The same seal can allow a suction leak from the mechanical fuel pump. It doesn't belong on your RV, and it definitely does not belong there.

If you are going to sump the gascolator each walkaround, then put one on. But, if you are going to treat it like a filter and service it once a year, save yourself some money and install a nice inline filter. They are a smaller heat sink.

In the 80's, it was very common to scrounge parts like this and switches and gyros from scrap aircraft..... That RV4 in all likelihood, got into the air for less that $25K. And I bet the owner had more fun with it than most owners of their $125,000.00 RV7's..... go figure.
 
Exhaust Gas

I would be more concerned about that hole, assumably aft of the exhaust stack and potentially a suction source into the cabin air.

I agree with others. Relocate it or replace it with a filter and plug that hole.
 
The filter idea is intriguing, since it should allow a drop in replacement that doesn’t require replumbing in that location. As far as the hole goes, I’ve never had any issues with it. My exhaust tips are turned down away from it, and I fly with a Sensorcon CO detector which has only ever maxed out at mid single digits PPM on the ground with a tailwind.
 
A gascolator is definitely not the lowest part of my fuel system (RV6 TD, Andair gascolator on the firewall). In my case, it filters the fuel - nothing more. And I’ve never seen anything in the gascolator bowl.
On my -6 the Gascolator (firewall mounted, brand name not apparent) is about the lowest point in the fuel system while in flight. I have found water and some small crud in the gascolator occasionally, so I know it's doing its job. As long as I get more than a gascolator's worth of water out of the tanks before flight, the gascolator will take care of the rest in flight and i'll get the rest out of it on the next pre-flight.
 
Gascolators.....

I was doing some minor/major work on the Cub and decided I needed to upgrade my (from a International Harvester tractor-looking) gascolator. A friend has a Steve's Gascolator on his PA-11 and I was impressed and ordered one.

It is a (more or less) direct replacement for the tractor-looking one that is most often used and is ****-for-stout brass and is NOT coming undone without being purposefully opened. The sealing mechanism is much better than the one (that looks like it's) from Tractor Supply (or JAX if you live in Colorado!). The quick drain is straight off the bottom which is a little more difficult to access in the Cub but still accessible. Take a look: www.stevesaircraft.com
 
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