FUJI-IMVAC BT-86 Operator’s Manual

Operator’s Manual for BT-86

SPECIFICATIONS

Displacement: 5.2 cu. in. [86cc]
Horsepower: 7.0hp @ 8500 rpm
Ignition Style: CDI Automatic

RPM: 1100 – 8500 rpm
Fuel: Gas/2-cycle engine oil
Weight w/Muffl er: 7.1 lb [3.2kg]

FEATURES

™

Ignition Timing

Decompression Valves

The valves are located in the center part
of each cylinder. Pressing this valve (one
or both) before starting will decrease
compression at starting. The valve on
the firewall side may be operated by a
servo for easier operation. Always use
the valves when using an electric starter.
The valves are closed automatically as
the engine fires. For restarting, press the
decompression valves again to open

The BT-86 engine features an electronic
ignition system. This system gradually
delays the ignition timing according to
the number of ignition pulses, increasing
with the engine speed. The fuel mixture
is ignited at almost top dead center when
idling and the timing is gradually increased
as the revolutions increase.

them.

Manufactured by FUJI-IMVAC INC.

YOKOHAMA, 235-0005 JAPAN

Worldwide Distributor (except Japan): Hobbico, Inc.

Champaign, IL 61826 USA

www.fuji-imvac.com

Fuji-Imvac is not related to the original Fuji Engines sold by Mecoa.

Entire Contents © Copyright 2009 FJIZ8600 for FJIG0086 V2

BEFORE OPERATION

1. Check to see that all screws and bolts are tight. Check carefully for any cracked,
broken or missing parts. Tighten or replace before proceeding.

2. Do not operate engine in a closed room or where ventilation is not adequate.

3. Check to see that there are no foreign objects in the path of the propeller. Secure
any loose articles of clothing so they cannot be drawn into the propeller.

4. Prepare only the amount of gasoline needed. Aged gasoline could damage the
engine and cause it to overheat.

5. Mix gasoline with 2 cycle oil only in the ratio of 40 parts gasoline to 1 part oil
(break-in ratio is 25 to 1.) Using fuel with an incorrect fuel/oil ratio or with oil
not intended for 2 cycle engines could cause damage and allow the engine to
overheat. Use an appropriate fuel fi lter to eliminate foreign matter.

6. Always allow engine to cool prior to refueling.

Break-in Operation

Operate engine for about one hour with a fuel mixture that contains a 25:1 fuel/oil
ratio. Do not break in by opening the high-speed needle on the carburetor. Carbon
will accumulate in the spark plug, which will make ignition diffi cult. (There is no
problem if break-in is done by fl ying the engine.)

STARTING PROCEDURES

Manual Starting:

1. Make sure the ignition is OFF. Close the choke plate on the carburetor and open
the throttle slightly from the idle position.

2. Rotate the propeller slowly about 10 to 20 times (more in Winter) until fuel
begins to move to the carburetor. (Swing the prop one-half turn to move the
piston from top dead center to bottom dead center, and then back to top dead
center repeatedly. Opposite rotation can also prime the carburetor.)

3. Turn the ignition ON and fl ip the propeller several times briskly.

4. Turn the choke lever to the OPEN position after you hear an initial fi ring and the
engine stops. You can squirt gasoline directly into the carburetor if the engine
does not fi re.

5. Rapidly fl ip the propeller until the engine starts. If the engine does not start,
repeat the steps 1-4.

6. After starting, let the engine idle for two to three minutes. Open and close the

2

throttle until the engine runs smoothly at idle and at full throttle. Acceleration
should also be smooth.

Safety Warnings:

For manual starting, make sure the propeller is properly adjusted on the propeller
shaft to allow you to rotate the fl ywheel past the ignition coil at the highest possible
speed during starting. Flip the prop rapidly from the point where you can fi rst feel
the compression.

Warning: Gasoline is volatile and fl ammable. Gasoline should be stored in
an approved container, away from heat or open fl ames. Do not smoke near
gasoline. Use caution when transporting gasoline and take precautions when
fueling your engine.

Starting With Optional Spring Starter (FJIG1086)

1. With the ignition OFF, close the choke plate on the carburetor and open the
throttle slightly from the idle position.

2. Rotate the propeller slowly about 10 to 20 times (more in Winter) until fuel
begins to move to the carburetor. (Swing the prop one-half turn to move the
piston from top dead center to bottom dead center, and then back to top dead
center repeatedly. Opposite rotation can also prime the carburetor but will not
be possible when using the spring starter.)

3. Turn the ignition ON. Hold the propeller, turn it clockwise 360° (one rotation) and
let it go. Turn the choke lever to the OPEN position after you hear an initial fi ring
and the engine stops. You can squirt gasoline directly into the carburetor if the
engine does not fi re. Repeat steps 1,2, & 3 above, as necessary.

Starting With Optional Electric Starter (Onboard type or External type)

1. With the ignition OFF, close the choke plate on the carburetor and open the
throttle slightly from the idle position.

2. Turn the propeller with the starter for a few seconds until fuel begins to move to
the carburetor.

3. Turn the ignition ON. Turn the propeller with the starter.

4. Turn the choke lever to the OPEN position after you hear an initial fi ring and the
engine stops. You can squirt gasoline directly into the carburetor if the engine
does not fi re. Again, turn the propeller with the electric starter.

Starting Without Using the Choke (Recommended after the engine is well

3