Arrow Shark Flying Dragon 2012 SV, Instruction Manual

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#1: The Low­Speed Needle: The low speed needle of the M­39 carburetor is hidden in the
center of the carburetor barrel. You need to use a small precision flat blade screwdriver to
adjust it. When adjusting the Low­Speed Needle, apply Loctite#222 on the needle thread in
order to hold the needle in position during operation. The Low­Speed Needle is set at 6­6 1/2
turns out from fully closed (or fully screwed in).
Note: when the M­39 carb is installed rotated in your boat, it is not easily to adjust the low
speed needle when you plan to make small adjustment to the low speed needle, you will
either need to take out your engine from your boat or uninstall the carb from the engine to do
the little adjustable, however, once you set the low speed needle correctly, you will never
need to adjust it again, from our timeless testing on our Pro­mod M­39 carb, the low speed
needle set to 6­6 1/2 turn out will work well on both stock or mod motor. And the carb was
Pre­set at 6 turn out from our factory.
#2: High­Speed Needle: The High­Speed Needle is set approximately 2 plus 1/2 turns out
from fully closed.
#3: Idle Screw: Set this at the lowest RPM where the engine idles reliable without stopping.
Screwing the idle screw in will make your engine rev faster.
Note:
Please take out the idle screw from the carb after you complete your radio setting.
4: Carburetor Adjustment Tips
When adjusting the needles from their standard settings, move them only 1/8 of a turn a time.
Check the results then adjust further as needed. Never attempt to tune the high­speed needle
by running the engine at full throttle out of the water! This is very dangerous and damages
the engine. The following tips may assist in setting your carb for optimum engine
performance.
A: Low­Speed Needle
If the engine is easy to start, and idles a little rough (rich), and responds well when you open
the throttle with a brief show of smoke through the exhaust, then the low speed needle is
close to being correct. If the engine tends to hesitate or bog down when you open the throttle
quickly (especially when the engine is cold), or if the idle speed is too high even with the
throttle barrel nearly closed, the low speed needle is probably to lean and you need to screw
it out (1/8 of a turn at a time). If the engine floods easily and is hard to start, the low speed
needle is probably set to rich and you need to screw it in slightly.
B: High­Speed Needle
When this needle is correctly set, the engine will run cleanly, accelerate well from half
throttle without hesitation, and will not lose RPMs during turns. It is tempting to lean the
high speed needle to optimize the mixture for peak power and on­water RPM, but going too
lean can be risky as the engine will suffer from overheating and reduced lubrication. This can
lead to damage or shorter life for your engine. If the engine stops or loses RPMs when your
boat is running on the water, the high speed needle is probably set too lean and you need to
screw it out slightly. If the engine is not running cleanly and seems to hesitate or not reach
peak RPMs, then the high speed needle is probably set too rich and you need to screw it in
slightly. Running with a slightly rich mixture may cause a small drop in top speed, but it will
allow your engine to run cooler and with good lubrication for reliability and long life.