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Old 04-12-2009, 01:25 PM
  #7  
karolh
 
Join Date: May 2002
Location: Mandeville, JAMAICA
Posts: 6,533
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Default RE: Newbie to Gas General Information

Excellent posts Bob, makes me wish that I had found something like this having so much of the good stuff in one place when I was starting out in gas.

Karol

The following is added by the moderator . . . .

Original:Antique
CARBURETOR 101[>:]....All Walbro and Tillotson carbs were originally made for something else, not a model airplane...The other users have a trigger to operate the throttle, hence the spring....All Walbros and Tillotsons have a clip or some means to keeo the shaft tight against one end...'
The spring has two functions, to return the throttle to idle and to keep the shaft against the clip or whatever centers is..
When a carb is wide open the disc does not completly fit against both ends of the hole in the carb, the venturi...
The spring's other function is to keep tension on the shaft to hold it against the end and not let it rattle around in the hole..
A carb with no meas to keep the dixc in the center will eventually get worn on one or the other or both ends to a point when the throtte is completely closed there is enough space on the ends to let fuel through and the idle will be too high...
I have been working on these things for at least 25 years and have seen quite a few worn carbs, both on the ends of the disc and both sides of the body wher the disc has been vitrating against it...
Take the spring off if you liike, if you fly long enough you will find that your idle will be too high and the engine can not be cut off with the throttle....PERIOD[>:] If this explanation offends anyone's tender ego, so be it, get over it, it is the truth...
Tillotson carbs have a brass washer and clip...And a spring.
Some Walbros have a clip on both sides, and a spring...
Walbro WTA6 G38 carbs have a spring on one side and a wider clip on the other end screwed into the carb body to keep the shaft centered...
Glow carbs generally have a rotaty barrel with a groove in one end. sometimes straight, sometimes spiral...there is a screw in the carb body with the end turned down to fit into the groove...Some have an internal spring....
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