This section will help explain how to setup your motor for best performance. This is not a page on engine hop-up parts,
but a "How To" adjust your motor from a stock setup point of view. There are many ways to hop-up a motor and maybe I will
include some information on hop-ups some day. This article deals with motors as they come out of the box. Here we go……
Now, that you have broken-in your motor ( you did break your motor in didn’t you?) your ready to proceed. If you
try to run your motor the way described next without a proper break-in. you will at the very least take years away from your
motors life. At worst you will make yourself a very expensive paper weight. Go to Motor Break-in if you Havn't broken it in.
High Speed Needle Adjustments. Setting up or resetting the high speed needle (or
needle valve as some call it) can be easy. If you follow the directions closely you should have no problem. If you follow
the following directions and it never seems to set right. Go to the trouble shooting section, or ask an experienced modeler
for help!!! Something maybe wrong.
Fill your fuel tank.
Prime your motor.
Apply power to your glow plug.
Using an electric starter or chicken stick start your motor.
Clear The Motor. Once your motor has started you may need to leave the glow plug
driver on till you cycle the throttle from idle to full throttle a few times. This should clear the motor of extra fuel from
priming if need be. Then remove the glow plug power. If the motor dies, lean the high speed needle a little. ¼ to ½ turn should
be good and try again. Repeat till motor will advance to high throttle and remain running when power to glow plug is removed.
Choose Your Method. Now there is several ways to do this next step. One is with
a tachometer, another is pinch and release method, and the other is with sound (by ear) If you have access to a tachometer
and you have little experience, then use it. If not DO the pinch and release method. If you have experience with motors (like
R/C cars) you might be able to do it by ear, if not, that will come over time.
Tachometer Method. Using a tachometer (follow tachometers instructions) take a reading
of the props RPMs. Now using the high speed needle, lean the motor slowly. You will see the RPMs increase. At a certain point
the rpms will not go higher and will even start decreasing. Stop and turn the needle the opposite direction. (richer) several
hundred RPMs. For example if the highest RPMs were reached at 16,500, you would want to richen the needle till the RPMs read
16,100. Now one final test. Hold your plane with the motor pointing straight up. If the RPMs increases slightly but the motor
doesn’t sage. That should be it, your motors set. Enjoy!!! If it does sage, then richen it a few clicks. When you hold
your plane motor up, you want to hear a slight increases in rpms without a sage. That is when you know your motor is dialed
Pinch and Release Method. Start your motor and advance to high throttle. Now pinch the
fuel line by the carburetor and release it quickly. If the motor speeds up slightly and then resumes it’s previous speed.
Lean the motor a few clicks and repeat. At a certain point the motor will not speed up when the line is pinched. When this
happens, richen it a few clicks. Now test the motor by holding your plane with the motor pointing straight up. If the RPMs
of the motor increases but your motor doesn’t sage, congratulations. Your motors set!!!! If it does sage, then richen
it a few clicks. When you hold your plane motor up, you want to hear a slight increases in rpms without a sage. That is when
you know your motor is dialed in.
Ear Method. If your using the ear method you should be familiar with R/C motors. Start
your motor from a rich setting. Start leaning the high speed needle. You should hear a constant increase in rpms. When the
rpms stop increasing or even start to fall a little, STOP! And richen the needle several clicks till you hear the rpms decrease
a few hundred rpms. Now one final test. Hold your plane with the motor pointing straight up. If the RPMs increases slightly
but the motor doesn’t sage. That should be it. If it does sage, then richen it a few clicks. When you hold your plane
motor up, you want to hear a slight increases in rpms without a sage. That is when you know your motor is dialed in.
Next we'll discuss the low speed needle and how to set it.
The low end needle valve is usually adjusted the same way as the high speed needle. Clockwise
is leaner and Counter Clockwise is richer. Some motors do not follow this though. The O.S. FP .40 is a good example. It is
opposite of the norm. Read your owners manual. If you’ve lost it, you can check out our link to Engine Manuals Page.
High Speed Needle must be set first. If you haven’t done so, do so now.
Clear The Motor. Now that your high speed needle is setup for best performance, it’s
time to set the low end needle valve. This is easily done. With a full fuel tank start your motor and clear it by cycling
through high and low throttle a few times. This will clear the motor of built up fuel from priming.
Motor Reaction. Now notice how the motor reacts when going from low throttle to
full throttle quickly. If it sputters and dies, it is set to rich. You may even notice fuel spitting out of the carburetor.
Turn the motor off and lean the low end needle about 1/8 turn. Restart and repeat the above steps.
Fine Tuning. At a certain point the motor will start transitioning from low to
full throttle with little hesitation or sputtering. The low end needle is now at a very critical point. The smallest 1/32
of a turn should be used as you dial it in. if at any point the motor sages and dies or loses RPMs, STOP immediately and turn
the low end needle the opposite direction.
Ask For Help! If for some reason the needle valve just will not set right, by all means
ask another pilot at the field for help. There may be something else wrong!!!!
When you can go from low to high throttle reliably with fuel not spitting out of the
carb or the motor sputtering and hesitating, your done.
Congratulations!!! You’ve just set your low end needle valve. Now wasn’t
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