engine YAMAHA GP800R 2021 Repair Manual

5-2
E
Engine runs irregu-
larly or stallsFuel Empty Refill as soon as possi-
ble3-3
Stale or contaminated Have serviced by
Yamaha dealer4-10
Choke Lever is moved to on Move back to original
position2-8
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer4-11
Fuel tank Water or dirt present Have serviced by
Yamaha dealer4-11
Spark plug Fouled or defective Replace 4-15
Incorrect heat range Replace 4-15
Gap incorrect Adjust 4-15
Spark plug cap Loose Connect properly 4-15
Cracked, torn, or dam-
agedHave serviced by
Yamaha dealer—
Electrical wir-
ingLoose connection Tighten or connect
properly—
Carburetor Incorrect idle adjust-
mentAdjust idle
4-21
Clogged Have serviced by
Yamaha dealer—
Warning light or
indicator blinksFuel level Empty Refill as soon as possi-
ble3-3
Engine oil level Empty Refill immediately 3-4
Oil filter clogged Clean 4-12
Engine over-
heatedJet intake clogged Clean
5-4
Low battery
voltageBattery voltage low Charge 4-19
Battery terminal con-
nected wrongConnect properly
4-19 TROUBLE POSSIBLE CAUSE REMEDY PAGE

5-3
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Wate rcr af t slow or
loses powerCavitation Jet intake clogged Clean 5-4
Impeller damaged or
wornHave serviced by
Yamaha dealer—
Engine over-
heatedJet intake clogged Clean
5-4
Fuel filter Clogged Have serviced by
Yamaha dealer4-11
Spark plug Fouled or defective Replace 4-15
Incorrect heat range Replace 4-15
Gap incorrect Adjust 4-15
Spark plug
capsLoose Connect properly
4-15
Electrical wir-
ingLoose connection Tighten or connect
properly—
Fuel Stale or contaminated Have serviced by
Yamaha dealer4-10
Bilge Water in bilge Drain 3-7 TROUBLE POSSIBLE CAUSE REMEDY PAGE

5-4
E
EJU00597
Emergency procedures
EJU00598
Cleaning the jet intake and
impeller
If weeds or debris get caught in the intake
or impeller, cavitation can occur, causing jet
thrust to decrease even though engine
speed rises. If this condition is allowed to
continue, the engine will overheat and may
seize. If there is any sign that the jet intake
or impeller is clogged with weeds or debris,
beach the watercraft and check the intake
and impeller. Always stop the engine before
beaching the watercraft.
WARNING
Before attempting to remove weeds or
debris from the jet intake or impeller
areas, shut the engine off and remove
the clip from the engine shut-off switch.
Severe injury or death could result from
contact with the rotating parts of the jet
pump.
1. Turn the watercraft on its side as shown.
CAUTION:
●Place a suitable clean cloth or carpet-
ing underneath the watercraft to pro-
tect it from abrasions and scratches.
●Always turn the watercraft over onto
its port (left) side.
●When turning the watercraft on its
side, support the bow so the handle-
bars cannot be bent or damaged.

5-5
E
2. Remove any weeds or debris from
around the drive shaft, impeller, pump
housing, and jet thrust nozzle.
If debris is difficult to remove, consult
your Yamaha dealer.
CAUTION:
Always avoid operating your watercraft in
areas where weed growth is thick. If trav-
eling in weeded areas is unavoidable,
operate the engine alternately at partial
throttle and full throttle. Weeds tend to
accumulate more at a steady speed and
at trolling speed. If weeds clog the intake
or impeller area and cause cavitation, fol-
low the cleaning procedure above.
EJU00599
Jumping the battery
If the watercraft battery has run down, the
engine can be started using a 12-volt bat-
tery and jumper cables.
WARNING
Battery electrolyte is poisonous and dan-
gerous, causing severe burns, etc. Elec-
trolyte contains sulfuric acid. Avoid
contact with skin, eyes or clothing.
Antidotes
External: Flush with water.
Internal: Drink large quantities of water
or milk. Follow with milk of magnesia,
beaten egg or vegetable oil. Call physi-
cian immediately.
Eyes: Flush with water for 15 minutes
and get prompt medical attention.
Batteries give off explosive gases. Keep
sparks, flame, cigarettes, etc. well away.
If using or charging the battery in an
enclosed area, make sure that it is well
ventilated. Always shield your eyes when
working near batteries.
KEEP OUT OF THE REACH OF CHILDREN.

5-6
E
EJU00600
Connecting the jumper cables
1. Connect the positive (+) jumper cable 1
to the positive (+) terminals of both bat-
teries.
2. Connect one end of the negative (–)
jumper cable 2 to the negative (–) termi-
nal of the booster battery 3.
3. Connect the other end of the negative (–)
cable to an unpainted bolt on the cylinder
head.
CAUTION:
Do not connect the end of the jumper
cable to the negative (–) terminal on the
watercraft battery! Be sure all connec-
tions are secure and correct before
attempting to start the engine. Any
wrong connection may damage the elec-
trical system.
4. Start the engine, and then disconnect
the cables by reversing the steps above.
CAUTION:
●Never push the start switch while the
engine is running.
●Do not operate the start switch for
more than 5 seconds, otherwise the
battery will be discharged and the
engine will not start. Also, the starter
motor may be damaged. If the engine
does not start in 5 seconds, release
the start switch, wait 15 seconds, and
try again.

5-7
E
EJU00603
Towing the watercraft
If the watercraft becomes inoperative in
the water, it can be towed to shore.
If the watercraft must be towed in an
emergency using a tow line, the operator
should ride the watercraft, holding onto the
handlebars.
CAUTION:
●Tow the watercraft slowly; water may
enter the air intake and flood the
engine compartment if the watercraft
is towed too fast.
●Tow the watercraft using the bow eye 1
only.
●The bow must be kept up out of the
water during towing to prevent water
from entering the engine compart-
ment.
WARNING
●The watercraft should only be towed in
an emergency.
●The tow line should be long enough so
that the watercraft will not collide with
the towing boat when slowing down. A
good rule of thumb is a tow line which
is three times the combined length of
the towing boat and the watercraft. A
shorter length of rope can be used if
the watercraft is towed very slowly.
●The operator of the towing boat must
keep speed to a minimum and avoid
traffic or obstacles which could be a
hazard to the rider on the watercraft.

5-8
E
EJU00604a
Submerged watercraft
If the watercraft is submerged or flooded
with water, follow the procedure below and
consult a Yamaha dealer as soon as possi-
ble. Failure to do so may result in serious
engine damage!
1. Beach the watercraft and remove the
stern drain plugs to drain the water from
the engine compartment.
2. Turn the fuel cock knob to “OFF.”
3. Remove the spark plugs and dry them
with a cloth.
4. Without reinstalling the spark plugs,
crank the engine until all the water in the
cylinders has been drained.
5. Install the stern drain plugs and the
spark plugs.
6. Turn the fuel cock to “ON.”
7. Launch the watercraft into the water, and
then run the engine for at least
10 minutes. If the engine will not start,
repeat steps above.
8. Turn the engine off. Turn the fuel cock to
“OFF.”
9. Remove the silencer cap and spray a
rust inhibitor into the carburetor while
cranking the engine.
10. Have the watercraft inspected by a
Yamaha dealer as soon as possible.

6-1
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EJU00609
Index
2-stroke engine oil ................................... 3-4
A
Adjusting the carburetor ........................ 4-21
Adjusting the trolling speed ................... 4-21
Adjusting the Yamaha Adjustable
Sponson (Y.A.S.) .................................. 4-23
Approval label of Emission control
certificate ................................................. 1-2
B
Battery .............................................. 3-8, 4-5
Beaching the watercraft ........................ 3-30
Bilge ........................................................ 3-7
Bleeding the oil injection pump ............. 4-22
Boarding alone ...................................... 3-23
Boarding and starting in deep water ..... 3-23
Boarding with a passenger.................... 3-24
Bow down.............................................. 2-12
Bow up .................................................. 2-12
C
Capsized watercraft .............................. 3-25
Caution labels ......................................... 1-7
Choke lever ............................................. 2-8
Cleaning and adjusting the spark
plugs...................................................... 4-15
Cleaning the jet intake and impeller ........ 5-4
Cleaning the watercraft ........................... 4-6
Connecting the jumper cables................. 5-6
Cooling water pilot outlet .............. 2-10, 3-12
Cruising limitations ................................ 1-10
D
Docking the watercraft .......................... 3-30
E
Emergency procedures ........................... 5-4
Emission control information ................... 1-2
Engine break-in ..................................... 3-13
Engine compartment ............................... 3-6
Engine overheat warning indicator ........ 2-18
Engine overheat warning system .......... 2-13
Engine serial number .............................. 1-1Engine shut-off cord (lanyard) ............... 3-11
Engine shut-off switch ............................. 2-8
Engine stop switch .................................. 2-8
Enjoy your watercraft responsibly ......... 1-15
F
Filling the fuel tank .................................. 3-3
Filling the oil tank .................................... 3-4
Fire extinguisher ...................................... 3-9
Flushing the cooling system .................... 4-1
Front storage compartment ................... 2-19
Fuel and oil.............................................. 3-1
Fuel and oil systems ............................... 3-6
Fuel cock knob ........................................ 2-7
Fuel filter ............................................... 4-11
Fuel meter ............................................. 2-17
Fuel system ............................................. 4-4
Fuel tank ............................................... 4-11
Fuel tank filler cap ................................... 2-6
Fuel warning indicator ........................... 2-18
G
Gasohol ................................................... 3-2
Gasoline .................................................. 3-1
Getting to know your watercraft ............ 3-19
Glove compartment ............................... 2-20
H
Handgrip ................................................ 2-14
Hazard information ................................ 1-13
Hood........................................................ 2-6
Hour meter ............................................ 2-17
Hull Identification Number (HIN).............. 1-1
I
Identification numbers ............................. 1-1
Important labels ....................................... 1-3
Inspecting and adjusting the throttle
cable...................................................... 4-13
Inspecting the battery ............................ 4-19
Inspecting the fuel system ..................... 4-10
Inspecting the oil injection system ......... 4-12
Inspecting the QSTS mechanism .......... 4-14
Inspecting the steering cable................ 4-13
J
Jet unit................................................... 3-11
Jumping the battery ................................. 5-5

6-2
E
L
Label location .......................................... 1-3
Learning to operate your watercraft ...... 3-19
Leaving the watercraft ........................... 3-18
Limitations on who may operate the
watercraft ................................................ 1-9
Location of main components ................. 2-1
Lubrication............................................... 4-3
Lubrication points .................................. 4-16
M
Maintenance and adjustments ................ 4-7
Multifunction information center ... 2-15, 3-12
O
Oil filter .................................................. 4-12
Oil tank .................................................. 4-12
Oil tank filler cap...................................... 2-6
Oil warning indicator.............................. 2-18
Operating your watercraft...................... 3-19
Operation .............................................. 3-13
Operation of controls and other
functions .................................................. 2-5
Operation requirements ........................ 1-11
Other labels ............................................. 1-8
Owner’s/Operator’s Manual and
tool kit ...................................................... 4-8
P
Periodic maintenance chart..................... 4-9
Post-operation checks........................... 3-31
Pre-operation check list........................... 3-5
Pre-operation check points ..................... 3-6
Pre-operation checks .............................. 3-5
Primary Identification (PRI-ID) number ... 1-1
Q
Quick Shift Trim System (QSTS)
selector.................................................. 2-11
R
Replacing the fuse ................................ 4-22
Reset button .......................................... 2-16
Riding watercraft with a passenger ....... 3-20
Rough water operation .......................... 3-30
S
Safe boating rules ................................. 1-15
Safety information ................................... 1-9Seat ......................................................... 2-5
Specifications ........................................ 4-24
Speedometer......................................... 2-16
Starting and boarding in shallow
water ..................................................... 3-22
Starting from a dock .............................. 3-22
Starting the engine ................................ 3-15
Starting the watercraft ........................... 3-21
Start switch.............................................. 2-9
Steering system ...........................2-10, 3-10
Stopping the engine .............................. 3-18
Stopping the watercraft ......................... 3-29
Storage.................................................... 4-1
Storage compartments .......................... 2-19
Submerged watercraft ............................. 5-8
Switches ................................................ 3-12
T
Tachometer ........................................... 2-16
Throttle .................................................. 3-10
Throttle lever ........................................... 2-9
Towing the watercraft .............................. 5-7
Transporting .......................................... 3-33
Troubleshooting ...................................... 5-1
Troubleshooting chart ............................. 5-1
Turning the watercraft ........................... 3-27
W
Warning labels ........................................ 1-4
Watercraft characteristics ...................... 1-14
Water separator ...................................... 3-7
Y
Yamaha Adjustable Sponson (Y.A.S.) .. 2-20