-3-
(B) Manual starting method (For safety, wear gloves and use a safety stick)
1. - 2. Same procedure as (A) describes.
3.
Prime the engine. Open the throttle valve fully by using the throttle stick. Insert a proper
length of silicone tube into the priming nipple. Use an injector to fill a proper amount
(1-2cc) of fuel into the carburetor.
4.
Manually crank the engine 2 to3 turns to supply fuel in cylinders. Then use the throttle stick
to fully close the throttle valve.
5.
Open the throttle valve about 1/4 to1/3 from the full close position by using the throttle stick.
(Starting with excessively opened throttle is dangerous since the airplane jumps forward.)
6.
Set the prop at the point of 30-45deg from the horizontal position, with the engine turned in
forward direction (CCW) to the position to be compressed.
Then heat the plugs.
7.
Swiftly crank the engine in forward direction (CCW) to start the engine..
G. Break-in
As Break-in is an important procedure to pull out the maximum performance of the engine, it must be cautiously implemented.
1.
After filling up the fuel tank, start the engine as described in the above section F. After starting the engine use the throttle stick to open the throttle valve to about half
open. Adjust the main needle while observing tachometer, exhaust oil concentration and exhaust concentration from the breather, to run the engine at 5,000rpm or
lower speed in rich condition for full tank fuel consumption. (Run the engine with plugs powered as required.)
2.
Next adjust the main needle and throttle valve opening to run the engine in rich fuel condition at 7,000 – 8,000 rpm for full tank fuel consumption. (In this stage also
observe tachometer reading, exhaust oil concentration and exhaust concentration from the breather.)
3.
Next fully open the throttle valve and adjust the main needle to run the engine at approximately 9,000 rpm for full tank fuel consumption.
4.
Finally adjust the main needle to run the engine at peak speed and less speed (richer) alternately. When the engine comes to run at a peak speed stably, ground break-in
has been completed for the time being. Now adjust valve clearance by following procedure of maintenance described later. Then adjust carburetor according to the
next article and make test flights at less speed around ten times to complete break-in. (Thereafter make flights at less speed, to prolong engine life.)
H. Handling and Adjustment of Carburetor
The SAITO carburetor has been adjusted on its slow needle to our reference value at factory default. The slow needle requires some correction depending on various factors
including the installation position, types of prop/fuel/plug, or climate conditions. Readjust the slow needle referring to the figure shown below.
[Reference value (only for a guide)]
Main needle: Open the needle by 2 turns from the full close point.
Slow needle: Fully close the throttle valve and slow needle CW to the end. Then open the slow needle by about 3 turns from the full close point.
1.
After filling up the fuel tank, start the engine as described in the previous section F.
2.
Fully open the throttle valve. Adjust the main needle while observing tachometer, exhaust noise and exhaust smoke, to attain the speed peak.
3.
Next control the throttle stick to gradually close the throttle valve to run the engine stably in the
range of around 2,000-2,500rpm. (Adjust the throttle stick while observing tachometer.
Exhaust smoke concentration, or exhaust/intake noise.)
a.
Rich fuel mixture: Turn the slow needle CW to make fuel mixture leaner.
b.
Lean fuel mixture: Turn the slow needle CCW to make fuel mixture richer.
4.
Once idling speed is set, fully open the throttle valve slowly. If the speed becomes irregular or
suddenly increases on the way, carefully adjust the slow needle so that the engine speed
changes linearly from the idling to the peak speed.
5.
When the above adjustment is completed, quickly change the speed from idling to the peak. If
the speed does not reach the peak on opening the throttle valve to full open point, return the
main needle by the amount single knurl notch gives. Then quickly change the speed again.
Repeat this procedure cautiously to attain the best response.
6.
When all conditions are set, return the adjustment of main needle slightly to lower the
maximum speed by 200-300rpm (make fuel mixture richer).
Caution: The purpose of break-in is initial adjusting of the master rod, link rod, bearings, gears and other mobile parts under the condition with rich fuel mixture.
Never make the fuel mixture lean. Lean fuel mixture could cause seizure even if the engine drops to idling and runs at low speed.
Note: Rotary units and slide ways of the engine have been lubricated at assembly with black molybdenum oil to prevent wearing or seizure. Hence black exhaust oil
comes out of the breather nipple and muffler at break-in operation. This could not be a trouble and you can continue the operation.
Note: Strictly avoid changing the direction of carburetor installation. Failure to do this will cause engine malfunction.
Caution: Excessive closing of main needle could cause knocking and give damage onto the engine. In such occasion, immediately turn the main needle CCW to make
fuel mixture rich.
Suppose the peak speed with the tank filled full with fuel is at 9,500rpm, set the main needle to reduce the peak speed by 300 rpm at 9,200rpm. Run the engine at a
speed about 300rpm lower than the peak to prolong the service life of the engine and minimize rusting on bearings.
Priming Method
Needle adjustment
