Hull And Hood - Yamaha GX1800A Service Manual

Major changes
1 Intermediate housing
2 Impeller
3 Impeller duct
4 Jet intake
5 Jet nozzle

Hull and hood

The large-sized sponson that is fitted on the F2S has also been adopted on the hull of this model to
improve the maneuverability.
1
1
Major changes
1 Sponson
2 Ride plate
To correspond to the higher output engine, the type of thrust
washer has been changed for better sealing performance.
The diameter has been increased from 155 mm (6.10 in) to
160 mm (6.30 in) to correspond to the higher output engine.
To correspond to the higher output engine, the number of recti-
fying fins has been increased from 6 fins to 8 fins. The number
of oil seals has also been increased for better sealing property.
Fins are added to improve water supply efficiency.
To correspond to the higher output engine, the nozzle diame-
ter "a" has been reduced from 86.8 mm (3.42 in) to 85.0 mm
(3.35 in) and the nozzle angle "b" has also been reduced from
5° to 3°, while the number of rectifying fins has been increased
from 6 fins to 8 fins.
The enlarged and relocated sponson improves the maneuver-
ability.
To correspond to the higher output engine, straight cruising
stability has been improved.
17
Description
2
2
Description