Section 3 - Initial Operation and Adjustment
The initial engine start must be preceded by accomplishing the following check list:
||The aircraft must be positioned with the cooling inlet facing
into the prevailing wind, its tail securely tied and wheel chocks placed in front of the
||Verify that the aircraft has sufficient fuel. Turn the
aircraft fuel valve ON.
||Both magnetos OFF.
||The idle mixture needle valve, located on the side of the
regulator (see Fig. 3-1.1 for EFS-4, -4-5, -5 and EFS-10), (see Fig. 3-1.2 for the EFS-2
and EFS-3A) as well as the idle throttle stop screw (Fig. 3-1.4) have been set at the
factory to a setting that should allow a successful first start. Either may be adjusted
with an Allen wrench if the need for adjustment is indicated in later testing (7/64"
for EFS-2 and EFS-3A and 7/64" for all other models).
||Set mixture control to FULL RICH.
||Set throttle to 1/2 throttle opening.
||Pressurize the fuel system by turning the electric fuel pump ON
or by operation of the manual fuel pump.
||With the fuel system pressurized and the throttle opened,
press a length of plastic tubing over the signal pressure ports as shown in Fig. 3-1.3 and
apply lung pressure to the oposite end of the plastic tube. This will open the inlet
control valve in the regulator and cause fuel to flow out of the metering tube. Continue
the application of lung pressure until fuel can be seen discharging from the metering
||Turn the electric fuel pump OFF.
||Prime the engine in accordance with the engine or aircraft
||Reset the throttle to about 1/8 inch opening.
||With the magneto switches both in the OFF
position, pull the propeller through 4 blades.
||Place the magneto switches in whichever ON
position is specified by the engine manufacturer for engine starting.
||Engage the starter or begin manual propping.
||If the engine does not start by the fifth compression stroke,
return to step 10. If step 10 has been repeated three times or if symptoms of flooding
occur, refer to Section 4-4 Unloading. Then return to step
||If the engine runs at a normal idle RPM and then dies after
consuming the prime fuel, turn the idle mixture screw (Fig 3-1.2 for the EFS-2 and
EFS-3A), (Fig. 3-1.1 for all other models) 1/2 turn counter clockwise and begin again at
||If the engine runs at very low RPM and then dies, increase
the idle throttle opening by rotating the idle throttle stop screw Fig 3-1.4 clockwise as
necessary to obtain stable operation.
|Fine tuning the idle adjustment is described in Section 3-4 and will be done after the engine has been thoroughly warmed up
by operation at full power.
||Both Magneto switches to OFF position at all
times except when engine is being started or is running.
Because the EFS-2 TBI may be installed on a wide range of engine sizes, a throttle stop
screw has been incorporated to permit the adjustment of the full throttle opening of the
EFS-2 to match the airflow requirements of the engine. This throttle stop has been preset
at the factory to approximate the needs of the engine specified in the customer's original
The following steps should be followed only if it is determined that the engine runs
rough, loses power, or is excessively lean at the full throttle position.
||Secure the aircraft with tie-downs and wheel chocks.
||If an absolute pressure manifold pressure gauge is installed,
note the reading that occurs prior to engine start. If a manifold vacuum gauge is
installed, confirm that the gauge reads "zero" prior to engine start.
||Start the engine and run at low power until the engine is
||Slowly open the throttle until the manifold pressure gauge
reads 1 to 1.5 inches of mercury less than the pre-start reading. If a manifold vacuum
gauge is used, slowly open the throttle until the manifold vacuum reads 1 to 1.5 inch of
||While the throttle is locked in the position established in
step 4 above, adjust the mixture control to provide peak RPM.
||With the mixture control secured in the peak RPM position,
confirm that the manifold pressure or vacuum gauge reading is unchanged from step 4.
||Mark, measure, or otherwise note the throttle position so
that this position can be reset following engine shutdown.
||Return the throttle to idle.
||After sufficient cool down, kill the engine by turning off
||Adjust the open throttle stop screw (located adjacent to the
mixture control arm) to limit throttle opening to the setting established in step 6 above.
||Start the engine and confirm that the throttle stop limits
the throttle opening as specified in step 4.
EFS-3A, -4, -4-5, -5, -10:
Engines operating with these models should not require any open throttle adjustment.
Any reluctance of the engine to run smoothly at full throttle is probably due to poor
inlet air duct geometry as described in Section 2-9 and
should be corrected as suggested therein.
The following procedure should be carried out with all inlet ducting removed. Because
the engine will be operated at full open throttle, a piece of 1/16 " mesh screen
should be secured over the bellmouth to prevent the ingestion of foreign debris.
||The aircraft must have its tail tied down and wheel chocks
must be in place.
||Start the engine and run at low power and full rich mixture
until the engine is properly warmed.
||Run the engine briefly at full throttle and adjust the
mixture control to yield an exhaust gas temperature 200 degrees F on the rich side of peak
temperature. If exhaust gas temperature instrumentation is not available, and if the
engine is equipped with a fixed pitch propeller, adjust the mixture so that engine speed
is reduced 50 RPM on the rich side of its peak value. If a constant speen propeller is
installed, adjust the fuel flow to the value specified by the engine manufacturer for the
RPM and manifold pressure observed at wide open throttle with the propeller governor set
to yield the engines maximum speed.
||While the mixture control remains fixed in the position
established in step 3, return the throttle to idle.
||After sufficient cool down at idle, kill the engine by
turning the magneto or ignition switch to OFF.
||With the engine off, install a full rich mixture stop in the
TBI mixture linkage to limit full rich mixture travel to the position established in step
3 above. This stop is usually most conveniently installed as a stop pin inserted into the
cockpit throttle quadrant. If a push push/pull cable is used for the mixture control, a
slit bushing of appropriate length can be installed over the push rod between the mixture
contro nob and the instrument pannel.
||Install the air filter and all inlet ducting. Repeat steps 1
and 2, then run the engine briefly at full throttle. Confirm the setting established in
step 3, and make additional adjustment if required. If roughness occurs at full throttle
with all inlet ducting in place, then excessive inlet turbulence is indicated. Consult Section 2-9 regarding inlet duct design.
The following procedure requires that the cockpit mixture control be placed in the full
rich position, and that the engine oil temperature be at least 100 degrees F.
||Start the engine and set the throttle to the desired idle
||If the engine is running with excessive richness or leanness,
correct by adjusting the idle mixture screw (Fig. 3-1.1 or Fig. 3-1.2). Clockwise to lean and counter clockwise to enrich.
||Adjust the idle throttle stop screw (Fig
3-1.4) as necessary to get desired idle RPM.
||Adjust the idle mixture screw to give peak RPM; then enrich
to decrease speed by 25 to 50 RPM.
||If idle RPM is different than desired, return to step 2.
Several iterations through steps 2 through 4 may be required.
||Following completion of the above, the engine should run at
the desired RPM with the mixture control in the full rich positions. Movement of the
mixture control to the full lean position should cause the engine to increase its speed 25
to 50 RPM before decreasing.
||Accelerate the engine from 1000 RPM to full power by sudden
throttle movement to wide open. If the engine stumbles or hesitates, then the idle mixture
must be enriched.
||Operate the engine at full throttle and exercise the mixture
control to confirm that full rich operation is 50 RPM or 200 degrees F. EGT on the rich
side of peak. If not, then repeat steps 3 through 6 of Section 3-3.
||Safety wire the idle throttle set screw.
||Use safety wire or cotter keys as appropriate to secure the
- Fuel filter housing plug
- Idle throttle set screw
- Ball swivel fitting on throttle arm (use supplied snap ring)
- Throttle cable clamp screws
- The regulator cover should still contain the factory installed safety wire and lead seal
- Both ends of pressure reference tubing (not applicable to EFS-2 and EFS-3A)
||Install all remaining induction system components.
After the TBI installation is completed in accordance with the preceding sections of
this manual, it should be inspected by an A&P or someone having equivalent technical
expertise in aircraft fuel systems. This independent second party inspection will minimize
the chance of some unsafe condition remaining undetected. Following the visual inspection,
the inspector should observe a ground run from idle to full static RPM, watching for fuel
leaks, excessive exhaust smoke or any other indications of unusual engine behavior. Any
discrepancies must be corrected prior to proceeding with the first flight (Section 5).
Following engine shutdown, inspect the engine, TBI, and all associated plumbing,
linkage, and ducting for signs of chafing, interference or leakage.
Following completion of the above inspection, install the cowling and any other items
necessary for final airworthiness.
Make appropriate entries in the aircraft log books and consult with the FAA regarding
any requirements they may have for revising the aircraft's operating limitations.
This court decision may affect your
ability to make insurance claims if you make changes to homebuilt aircraft after initial
certification without consulting the FAA.
To Section 4