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HomeAircraftHelicopterGasser Model RC HelicoptersOther › Baron Gasser Carb Problems!
05-05-2005 09:57 PM  13 years agoPost 1
Derek Round

rrNovice

Bradford, UK

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Just refurbished a Baron Gasser, and am not familiar with the carb, so any help appreciated!
I can't get any fuel into the carb!
The carb has two pipes connected to its top, which go to the tank, and the tank has a vent to the underside of the heli. As you look at the carb, the RH pipe which connects to an L connector on the carb, goes to the tank vent, and the LH pipe connects to the clunk in the tank.
On the RH side of the carb is a squashy blobby think that pumps, not fuel (as it stands) but air to the tank. So with the vent open it pumps absolutely nothing as the pumped air is vented.
Aha, I thought, plug the vent and the pumped air will blow the fuel to the carb, which it does, or rather the tank gets pressurised, but no fuel flows to the carb.
Help!
Several questions...is the plumbing correct, and if so...what am I doing wrong....and how do I fix it?
And which twiddly screw underneath controls what mixture?
By the way, the engine runs on a "prime" through the carb, so the ignition system seems fine at this stage.
Thanks in anticipation to all those helpers out there!
And I'm really looking forward to getting it in the air!

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05-05-2005 10:25 PM  13 years agoPost 2
AGRAV8

rrProfessor

Mosquito Coast......Houston Texas

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OK
here is what is going on.

the RH tube coming off the carb is the return line (it is closest to the primer bulb) and it allows extra fuel to go back to the tank, as the carb does not have a "bowl" to keep extra in it.

The primer bulb DOES pump fuel, but there will ALWAYS be some air trapped in it. About 3/4 full of fuel is all you can expect.

The return line to the tank shouldn't go to atmosphere, it should go to the tank only, and there should be a line from the top of the tank itself for venting.

The clunk line should NOT have any "t" or break in it.

Take the return line off the carb to fill the tank.

Those needles below are not to be taken lightly, as they are very sensitive and a small movement makes a big difference when they are tuned correctly.

You need to get the model of that carb. Probably a 167A, 197A, 603, or 643. Also, what engine does this machine have?

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05-05-2005 10:40 PM  13 years agoPost 3
Derek Round

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Bradford, UK

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Well, things are getting clearer! Thanks for your help, aggrav8.
Right, so the return line should go to the tank, and it does.
So, the tank needs a normal vent.
But, squeezing the primer bulb should pump some fuel (and air) back to the tank. But it only pumps air to the tank, AND I can't get any fuel into the carb by the normal feed line.
SO, the feed line is blocked! I feel a carb stripdown coming on tomorrow evening. Any pointers?
Will post the carb model number shortly after that.
Thanks again!

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05-06-2005 12:19 AM  13 years agoPost 4
AGRAV8

rrProfessor

Mosquito Coast......Houston Texas

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Check this
make sure that the clunk line is OK and able to pass fuel thru it by removing it from the carb and holding it BELOW the level of fuel in the tank. It should flow freely.

When you take the carb apart, there is a screen inside (you cannot miss it) and also may be one on a hole in the carb body. Make sure they are not clogged.

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05-07-2005 04:44 PM  13 years agoPost 5
Derek Round

rrNovice

Bradford, UK

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Right! Have stripped the carb, and all appears fine. Put it back together and no change to the problem!! BLAST!
So, (its a wa167 by the way), had a real good look at which does what, great fun following all those drillings, diaphrams and flap valves (quite impressed with the quality!) and have determined that what is normally the "float level needle valve on a conventional carby", is permanently closed. Working from first principles, I THINK this valve should be held open by something (a light missing spring?) and when a certain petrol pressure is attained (by the separate pump), this pressure acts on the diaphram (and that light spring) and closes the supply needle valve, so keeping the supply pressure at the jets constant.
SO, either I'm missing a light spring, OR maybe the diaphram was originally manufactured so it was "springy" in the right direction, Or maybe there is some other factor I've not thought of?
What would really help is some sort of exploded diagram, schematic or something....I have had a browse on the net but no luck at all so far, which is why I'm here!
Help and comments, please.
As I've said before, I'm most grateful for all help given so far!

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05-07-2005 05:01 PM  13 years agoPost 6
Bushy

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Tucson, AZ

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05-07-2005 11:02 PM  13 years agoPost 7
Derek Round

rrNovice

Bradford, UK

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Success!
Thanks to you both.
The fix was the resetting of the arm that controls the needle valve that is operated by the diaphram.
Thanks again!

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05-08-2005 03:32 AM  13 years agoPost 8
Bushy

rrVeteran

Tucson, AZ

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