Synchronizing The Throttle Valves - Yamaha F150A Service Manual

Synchronizing the throttle valves

CAUTION:
Do not adjust the throttle valve when it is
operating properly. Excess adjustment
may cause poor engine performance.
1. Remove the caps 1, and then attach the
special service tool to the intake manifold
as shown.
Vacuum gauge: 90890-03159
2
3
63P3F11
Intake assembly and vapor separator
NOTE:
For best results, use a vacuum gauge (com-
mercially available), like 2 or 3 shown in the
illustration, that has four adapters.
2. Start the engine and warm it up for 5 min-
utes.
3. Attach the special service tool to spark
plug wire #1 4, and then check the
engine idle speed.
1
S63P4210
4. Check the vacuum pressure of all cylin-
ders.
1
S63P4220
4
Digital tachometer: 90890-06760
Engine idle speed: 700 ± 50 r/min
1
2
3
4
S63P4250
5
6
7
8
9
4-16