|
Twisted Sticks October 2006 Newsletter
Personal
Yes, I'm in Dumas again. I've been here putting together a weld
cell. Two work stations positioned 90 degrees apart on the sides of
a truncated triangle with a Fanuc Arc-Mate 100iB robot and a Lincoln
Power Wave 455M microprocessor power supply. I've been here 2 and
one half weeks. It was supposed to be 3 and a half weeks but my
partner in crime John Hanks our weld technician extraordinaire has
had his travel plans changed at the last minute. So I get sprung
early. I should even be able to make the meeting.
Nomination of Officers
The October meeting is for nomination for officers. We will be
voting for officers at the November meeting. Gentleman may I remind
you to nominate and then to vote. This is your club and it's
officers reflect you. (Man you know you are in trouble, when you
have me as your secretary!)
Tuning of air bleed two Strokes
Last month we talk about tuning a 2 needles carb. This month it's
an air bleed carb. So how do you tell the difference? The air
bleed carb has a small hole in the front of the carb near the top.
On the side is a small screw fitted with a spring that screws into
the hole. If you look carefully into the hole you should see that it
is partly blocked by the end of the screw. The hole allows air to
leak in to the carb thereby leaning out the mixture. The screw
regulates the size of the hole which changes the mixture. Now the
important part. It operates exactly backwards from a two needle low
speed valve! You turn it counter-clockwise to lean it. Remember a
bigger hole means a leaner mixture. Rough setting of the bleed
screw is so that you can see the needle centered in the bleed hole.
Everything else is the same as tuning a two needle carb.
First you must set the high-speed needle valve. After the engine
starts and is warmed up open the throttle to the full open position.
Unscrew the main needle by turning it counter clockwise, if the
engine slows, it is on the rich side of the setting, slowly turn the
needle in clockwise (turn an 1/8th to a 1/16th of a turn and pause
for 5 seconds) until the pitch of the motor is at it's highest or
use a tachometer. It's very important turn it back three or four
clicks or a minimum of 200 to 300 RPM. Running it at the maximum RPM
will be too lean in the air and will damage the engine. I usually
run mine 400 RPM less than peak.
If the motor speeds up, it is on the lean side of the setting,
continue unscrewing the needle until the engine begins to slow. Now
you are on the rich side of the setting, slowly turn the needle in
until the desired mixture is achieved as described above.
This time we will use the pinch method to determine low speed
adjustment. Some people feel it's easier.
Once the high speed (full throttle) mixture has been set it's time
to set the idle. Do the following with the battery disconnected from
the glow plug. Slowly close the throttle until the engine is close
to stopping. It may actually stop if you go too far but you will
then have some idea of just how slowly it will run reliably. When it
is at its slowest consistent idle, pinch the fuel tubing between
your fingers. If the mixture is set correctly the engine will pick
up a few revs after about a second before suddenly dropping in revs.
Let the tubing go as soon as the revs start to drop and the engine
should keep running at its normal idle speed.
If the revs drop immediately the tubing is squeezed then it is too
lean, conversely, if the engine revs increase quite a bit over
several seconds then it is too rich.
Next Meeting
Thursday the 11th at the field or Dales house if the weather doesn't co-operate.
|