Automatic Advancing Timer - Yanmar 4LHA-HTP Operation Manual

Chapter 3 Fuel Injection Equipment

5. Automatic Advancing Timer

5. Automatic Advancing Timer
5-1 Timer construction
The faster the engine s p e e d , the larger the crank angle
is during ignition delay.
ignition time and thus a decrease in engine output.
When an engine is used f r o m low to high speed, the
injection timing must be changed according to engine
speed to maintain it at the optimum timing.
The automatic timer uses centrifugal force to auto-
matically adjust injection t i m i n g .
Model
Identification code
Advanced angle
C i r c l i p -
Spring r e t a i n e r — ©
Spring guide
Timer hub Shims
Retainer
Flyweight
Identification code
This results in a delay in
See separate service data
Timer assy.
5-2 Function and characteristics of timer
The flyweights are pressed against the center of the
flyweight by the springs.
centrifugal force of the two flyweights increases,
compresses the timer springs, and the relative position
of the timer gear and hub changes according t o the
function of the retainer guide groove of the weight
and the weight guide of the timer gear, changing the
injection timing.
pressed (according to the rise in speed advancing the
timing), the advancing angle remains
to speed.
The advancing characteristics can be changed by chang-
ing the profile of the retainer guide groove of the
weight and the spring constant and setting force of
the spring
3-2-38
i 4LHA Series
A s speed increases, the
Accordingly, as the spring is com-
proportional
Engine speed