Yamaha F2.5A Service Manual page 137

Compression pressure
Check that there is no secondary air intake on the contact surfaces of
the carburetor.
Is there air
intake?
No
Check the compression pres-
sure of the combustion chamber.
Symptom: The engine idle speed is not steady, but increases or decreases.
• Check the intake manifold.
• Check the air intake system.
• Check the ignition system.
Check the operation of the
throttle cable and throttle link.
Good operat-
ing condition?
Yes
Check the ignition timing.
Out of
specification?
Yes
Check the TCI unit air gap.
69M3E11
Yes
Replace the respective seals.
No
Adjust the throttle cable and
throttle link.
No
Check the secondary air intake
on the O-ring and the gaskets.
Power unit
1
2
3
4
5
6
7
8
9
9-4