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-   -   Need a decent fuel filler valve, giant scale (https://www.rcuniverse.com/forum/gas-engines-142/171424-need-decent-fuel-filler-valve-giant-scale.html)

sagacity 06-22-2002 05:26 PM

Need a decent fuel filler valve, giant scale
 
1 Attachment(s)
Tried the Du-Bro Kwik-Fill and the Great Planes equivalent. Both suck air at mid throttle settings, and are unacceptable. How do these even stay on the market? Mine failed from three fuelings, thankfully before the plane flew.

I need bullet-proof fueling of a 32oz tank through a cowl or fuse mounted valve. I have a Dave Brown pump and am perfectly happy with that for pumping and purging, but this air bleed thing has to go.

Who's got it?

greg

kevin mcgrath 06-22-2002 06:03 PM

Need a decent fuel filler valve, giant scale
 
Use a fuel dot and two or three lines.One line is the open vent.Second line can be the klunk carb feed line only,or you can install a T in the carb line and run it to the fuel dot.If you do not use the T,the third line goes to the fuel dot and is used for filling only.I have tried two and three lines and both work well.
I have pretty much settled on two lines,cause its simpler,and you can fill and empty the tank from it......There are other variations using a second klunk for example but the fuel dot will solve your filler leakage problems .

sagacity 06-22-2002 07:58 PM

Need a decent fuel filler valve, giant scale
 
One of the things I liked about the concept of the fillers was the fuel cut-off to the carb during fueling. Is this a big deal? I know the 'flood and flip' adage about gassers, but don't want to go filling the cowl with gas, either. Is this a legitimate concern? And who makes the 'dots'?

Thanks for the reply!

greg

OUTCAST 06-22-2002 09:05 PM

Need a decent fuel filler valve, giant scale
 
I could be wrong about this but I don't think the diaphragm carbs we use will allow fuel to flow without the engine running. I agree with Kevin and use a third line, except I set it up as a second vent, to empty the tank I just turn the fuse over. It can be filled or emptied from either line. Greg, your not alone, the filler valves I have tried have all failed.

INJUN_EAR 06-22-2002 09:13 PM

Need a decent fuel filler valve, giant scale
 

Originally posted by sagacity
One of the things I liked about the concept of the fillers was the fuel cut-off to the carb during fueling. Is this a big deal? I know the 'flood and flip' adage about gassers, but don't want to go filling the cowl with gas, either. Is this a legitimate concern? And who makes the 'dots'?

Thanks for the reply!

greg

It's perfectly acceptable to fuel using a tee in the carb line. Gassers do not have the same problem glow engines have with flooding. No fuel will flow through the carb during fueling.

I use the two line system Kevin describes. I don't use dots anymore but rather use the B&B fuel fittings (personal preference).

kevin mcgrath 06-22-2002 09:20 PM

Need a decent fuel filler valve, giant scale
 
Agree with injun....gas carbs cant flood under fueling pressure since it takes at least crankcase pressure to move the membrane in the pump portion of the carb and you are nowhere near that level when fueling......
I also have been meaning to try the B&B product to see how it works......looks good in their catalog....

Big_Bird 06-22-2002 10:48 PM

Need a decent fuel filler valve, giant scale
 
One neat trick that I noticed was when a guy used a "T" in the vent line. One leg goes to the tank vent. Another leg goes outside the bottom of the airplane (normally plugged). The other leg has a check valve which lets air in to the tank vent but does not let fuel spray on the airplane during manuvers or drip out while walking the plane down the taxi way. Of course, I'm talking about a gasoline engine. This line is never capped off. When he fills the tank, he removes the plug from the vent line and replugs it when finished filling.

Does anyone know where I can get one of these check valves? One answer might be: " Go down to your local chainsaw repair shop and ask for one". When I do that they open this humongous parts book and ask "What brand chainsaw was that" with a big blank stare. I haven't had much luck getting anything at a chainsaw shop unless it's for a chain saw.

Ken

kevin mcgrath 06-23-2002 01:04 AM

Need a decent fuel filler valve, giant scale
 
Anyone selling smoke equipment carries one type or another of check valves in the right dia for typical gasser fuel tubing.DuBro squeeze pumps have one.Cheapest has to be the chain saw small engine emporiums if you can get them past the parts books.

stomper 06-23-2002 12:49 PM

Check Valve
 
Tower sell's Fourmost check valves.
Best set up is with a three line tank And fuel dot.

Danny Ray-RCU 06-23-2002 02:10 PM

Need a decent fuel filler valve, giant scale
 
Why bother with a check valve?A tee in the fuel line and a vent is all that is needed. When the engine is running there is actually a suction on the vent line. How much suction is needed to open the check valve?Seems like youcould maybe restrict flow.No air in means no fuel out. Better to keep it simple.

OUTCAST 06-23-2002 04:05 PM

Need a decent fuel filler valve, giant scale
 
Hey guys, why are you making this so complicated? Just run two vent lines side by side from the top of the tank out the bottom of the cowl. No plugs, no dots, no check valves, no pieces to loose or fail, totally maintenance free, fill through either line, turn it over and drain through either line. It's so simple even I can do it!

Big_Bird 06-23-2002 08:09 PM

Need a decent fuel filler valve, giant scale
 
Outcast, why didn't I think of that? It's really good when someone can come in and straighten all us dummies out. Thanks for your insite.

Ken

Geistware 06-23-2002 08:11 PM

Need a decent fuel filler valve, giant scale
 
I have one plane with two lines, fuel dot and the "T" and another plane with two vents and straight carb plumbing with no fuel dots. The two vents is easier! I do worry about siphoning with the two vents. Either my G45 is not as economical as my Brison or something is sucking gas out of the two vent system.

OUTCAST 06-23-2002 09:13 PM

Need a decent fuel filler valve, giant scale
 
Big Bird, sorry if you found my post insulting, my point that apparently you have missed, is that I have seen all of these fancy fuel systems fail, sometimes with disastrous results. This hobby is not cheap and I can't see loosing $500+ dollars worth of aircraft because of a crack in a 75 cent fuel "T", however "to each his own" so they say.

kevin mcgrath 06-23-2002 10:09 PM

Need a decent fuel filler valve, giant scale
 
A two line "T" fuel dot system is not "fancy",is as simple as it gets, and cant fail.Turning my 30# Bipe upside down to empty the tank seems silly.is going to eventually lead to handling damage of the model,and makes my back sore just thinking about it......

sanjoh 06-23-2002 11:10 PM

Need a decent fuel filler valve, giant scale
 
sagacity,

Would you like to sell your qwik fuelers?

I've used em for 4 years for glow and gas with no failures to date. Likely that my sample size is over twenty to date.

I gave my Dave Brown six shooter to the first person that would take after I tried it! That thing wore me out, I feel for the person trying to fill a large tank.

sagacity 06-23-2002 11:57 PM

Need a decent fuel filler valve, giant scale
 
Hey, all.

Two questions.

One, what's better than the Dave Brown Six-Shooter, and two, who makes the fuel dots?

On the dual vent system, seems simple enough, especially since the tank stopper is plumbed for three lines and gassers don't need pressure.

How 'bout this:

Vent one: Standard tank vent.

Vent two: toss a clunk on it and use it for fueling and purging only, and plug it for flight (a dot, if I could figure out who makes 'em!).

Any one got an objection to two clunks in the tank? I can see already that this might go either way....

How about a 'half-clunk', basically a clunk fitting on a piece of Tygon 1/2 as long as the clunk feeding the engine? Erk, that won't fully purge...


Thoughts?

greg

And on the sale request: I would not sell bad meat, and I would not sell a defective part. Perhaps I got a run of bad luck in the parts department, but the fuel valves I have are bleeding air to the tune of 50% of the volume of the carb fuel line. That's bad. Not only for fuel starvation, but, like any other part of a fuel-lubricated engine, the diaphragm fuel pump in the carb expects, and deserves, a full 100% cooling lubricating bath for its effort. There's a thread over yonder about the malfortune of having that diaphragm fail.

I found instructions for troubleshooting the valves, and now understand...the o-rings are press-fit in, and are at great risk of catastrophic damage from the insertion if it's not done right. I dessected the first one, and the flashing was not even removed from the o-ring before insertion...read particulate pollutant, factory-installed.

The hands that built the valve are at fault, for not trimming or rejecting the o-ring. Was a whole batch bad? If a bag of o-rings is full of defects, are there hundreds or thousands of wrecks hanging on the shelves of hobby shops in little plastic bags?

I'm talking myself into the simple tee, over which I have the most control...


cheers!

AJF--2 06-24-2002 12:56 AM

Need a decent fuel filler valve, giant scale
 
What I do is this----
1-klunk fuel line to carb
2-vent line with tube bend pointed to top of tank
3-vent line with tube bend pointed to bottom of tank stopping at almost the bottom---I use this line for filling and draining--I use the B&B chrome screw type plugs for this line.

Mike Wiz 06-24-2002 11:32 AM

Need a decent fuel filler valve, giant scale
 
I've just rigged my H9 Cap fuel system with a Dubro filler. I knew they had a tendency to leak air, so I ran a three line system: one line to the carb, one to the overflow and one to the Dubro filler.

I haven't used it yet, but a good on-line friend, Branwell McClory, once told me he used this very same setup with good results.....we'll see.

Wiz


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