Stihl Edt 8 Manual

							STIH)
Technical Information
TI_10_2006_30_01_01.fmenglisch / English USA
New STIHL special tools
Contents
1. New tachometers EDT 7 and EDT 8
1.1 New ignition systems
1.2 Tachometer EDT 7
1.3 Tachometer EDT 8
1.4 Antennas supplied with the units
1.5 Method
1.6 Battery life
1.7 Pictograms in the supplement for the EDT 8
1.8 Hour meter
1.9 Summary 
1. New tachometers EDT 7 and 
EDT 8
1.1 New ignition systems
The development of new ignition systems has made 
it necessary to use new tachometers.
The principle of operation underlying the new 
ignition systems is different from that of the 
standard ignition system.
Both pairs of poles are used to generate electrical 
pulses. One pair of poles is used to generate the 
energy for ignition. The other pair is used to 
generate pulsating electrical power which can be 
used for various purposes, depending on the design 
of the ignition system.
The new ignition systems used on some models can 
be identified by their flywheels with two pairs of 
magnetic poles.
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The second pair of poles generates a relatively high 
impulse voltage which is registered by the 
tachometer and used for indication of the speed, 
depending on the instruments electrical design. 
This means that, for every revolution of the flywheel, 
the tachometer can indicate two revolutions of the 
power unit, which effectively constitutes a 
measuring error.
The new tachometers are designed and built in such 
a way that they only process and indicate the 
ignition pulses of the new ignition systems.
The purposes for which the second electrical pulse 
is used are described in the Technical Information 
bulletins issued when a power tool with newly 
developed ignition system is launched on the 
market. 
1.2 Tachometer EDT 7
The new tachometer EDT 7 supersedes the 
previous version EDT 5. Both versions are 
characterized by the fact that they can be adjusted 
to the operating principle and ignition system of the 
engine concerned by changing the setting.Features of the EDT 7:
- Used for engines with one cylinder
- Used with two-stroke and four-stroke engines 
with one ignition pulse for each revolution of the 
crankshaft. Can be adjusted for one pulse per 
two revolutions.
- Storage and indication of the maximum speed
- Operation and adjustment of settings via a 
single button
Operation of the EDT 7 is described in a manual 
supplied with the unit.
The previous tachometer EDT 5 can continue to be 
used for standard STIHL ignition systems.
1.3 Tachometer EDT 8
The new tachometer EDT 8 supersedes the 
previous version DET-303.
Features of the EDT 8:
- Used for engines with one cylinder
- Used with two-stroke and four-stroke engines 
with one ignition pulse for each revolution of the 
crankshaft
- The setting cannot be changed
Operation of the EDT 8 is described in a supplement 
enclosed with the unit (see also 1.7).
The previous tachometer DET-303 can continue to 
be used for standard STIHL ignition systems. Left: Previous version EDT 5 – 
Part No. 5910 850 1006
Right: New version EDT 7 – 
Part No. 5910 850 1008
901TI041 KN
Left: Previous version DET-303 – 
Part No. 0464 801 0000
Right: New version EDT 8 – 
Part No. 5910 850 1009
901TI050 KN 
						

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1.4 Antennas supplied with the units
The two new tachometers are supplied complete 
with two antennas of different lengths:
- Test line (A) with a length of approx. 24 in 
(60 cm) and a terminal which is clamped directly 
onto the insulation of the ignition lead or spark 
plug boot.
- Short antenna (B) with a length of approx. 6 in 
(15 cm) for measurement without contact.
Both the test line and the antenna can be attached 
to the housing in the same simple way, as illustrated 
above.1.5 Method
1.5.1 Measurement with test line
Pulses should be measured with the test line. This 
method yields the most accurate results. 
.Clamp the test line onto any point on the 
insulation of the ignition lead or spark plug boot.
1.5.2 Measurement with short antenna
This method is useful for measuring the speed of 
engines in which it is difficult or impossible to clamp 
the test line onto the ignition lead or spark plug boot.
A
B
901TI043 KN
901TI044 KN
1.
2.
901TI045 KN
A
901TI046 KN 
						

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During measurement:
.Ensure that distance (A) remains between 
4 and 8 in (10 and 20 cm).
.Direct the antenna towards the pulse-
conducting parts of the ignition system.
Steady indication of the speed on the display means 
that the tachometer is properly aligned. 
1.5.3 Measurement with built-in antenna
This method is useful if a test line cannot be used 
and when the measurement must be made close to 
the engine or to the pulse-conducting parts of the 
ignition system.
During measurement:
.Keep distance (B) as short as possible 
(max. 2 to 4 in (5 to 10 cm)).
.Direct the built-in antenna and the arrow on the 
unit towards the pulse-conducting parts of the 
ignition system.
Steady indication of the speed on the display means 
that the tachometer is properly aligned.
Preference should be given to the measurement 
methods outlined in 1.5.1 and 1.5.2.1.6 Battery life
The battery in the two new tachometers cannot be 
replaced. The battery has a service life of 
approximately ten years in normal use.
1.7 Pictograms in the supplement for the 
EDT 8
Operation, the essential technical data and the 
units use are explained by means of drawings and 
pictograms in the supplement enclosed with the 
EDT 8. 
1.7.1 Explanation of pictograms
Use
 
B
901TI047 KN
ATwo-stroke engine with one cylinder and one 
ignition pulse for each revolution of the 
crankshaft.
BSTIHL 4-MIX
® engine with one cylinder and 
one ignition pulse for each revolution of the 
crankshaft. Four-stroke engine with lubrication 
by the fuel mixture.
CFour-stroke engine with one cylinder and one 
ignition pulse for each revolution of the 
crankshaft. Engine with separate lubrication.
901TI048 KN
ABC 
						

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Technical data
 
Disposal 
1.8 Hour meter
The new EDT 7 and EDT 8 tachometers do not have 
an hour meter function
1.9 Summary 
Last Technical lnformation on STIHL special tools: 23.2005
© ANDREAS STIHL AG & Co. KG, 2006 Technical Documentation
D1/MTK-na –
 40 °C to +70 °C
–
 40 °F to +158 °FOperating temperature 
range
0–16 000 1/min
0–16,000 rpmMaximum range for 
indication of the speed
Electrical devices must not be disposed 
of as household waste. The device, 
accessories and packaging should be 
recycled in an environment-friendly 
manner.
901TI049 KN
Item Part name Previous New Remarks
1 Tachometer EDT 5 5910 850 1006 - - - 1)
2 Tachometer DET-303 0464 801 0000 - - - 1)
3 Tachometer EDT 7 - - - 5910 850 1008
4 Tachometer EDT 8 - - - 5910 850 1009
Remarks
1) Previous version of part only remains available while stocks last.