engine YAMAHA GP800R 2021 Workshop Manual

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EJU00516a
Storage
WARNING
Always place the fuel cock knob in the
“OFF” position when storing the water-
craft, otherwise fuel could leak out into
the engine or engine compartment,
which would create a fire hazard.
Storage for prolonged periods of time,
such as winter storage, requires preventa-
tive maintenance to ensure against deterio-
ration. It is advisable to have the watercraft
serviced by a Yamaha dealer prior to stor-
age. However, the following procedures can
be performed by the owner.
EJU00913a
Flushing the cooling system
Flushing the cooling system is essential
to prevent the cooling system from being
clogged with salt, sand, or dirt.
CAUTION:
●Do not supply water to the cooling
water passages when the engine is not
running. The water could flow back
through the muffler into the crankcase
causing severe engine damage.
●Do not run the engine for more
15 seconds without supplying water,
otherwise the engine may overheat.

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1. Put the watercraft on land in a horizontal
position.
2. Open the flushing hose connector cap 1,
and then inser t the garden hose adapter
2
into the flushing hose connector 3 and
turn it until it is securely connected.
3. Connect the garden hose adapter to a
water tap using a hose.
4. Start the engine, and then immediately
turn the water supply on until water flows
out continually from the cooling water
pilot outlet.
5. Run the engine at idling speed for about
3 minutes watching the engine condition.
If the engine stops while flushing, turn
the water supply off immediately and
repeat the above steps.
6. Turn the water supply off, and then force
the remaining water out from the cooling
passages by alternately squeezing, and
releasing the throttle lever for 10 to
15 seconds.
7. Stop the engine.
8. Remove the garden hose adapter and
secure the cap.

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EJU00526a
Lubrication
WARNING
To reduce the risk of fire or explosion:
Never pour or spray gasoline, or any sub-
stance other than engine fogging oil
through the holes in the carburetor
silencer cover.
CAUTION:
●Be sure to replace the caps securely
after fogging the engine. Otherwise
water could enter the engine and
cause damage.
●Do not attempt to run the engine at full
throttle or for more than 15 seconds
while the watercraft is out of the water,
otherwise the engine may overheat
and/or seize.
1. Open the silencer cap 1 on the silencer.
2. Start the engine with the watercraft in a
well-ventilated area.
3. With the engine running at a fast idle,
quickly spray as much fogging oil as pos-
sible through the hole in the silencer
cover. Keep spraying until the engine
stalls (or a maximum of 15 seconds).
4. Install the cap securely.
5. Remove the spark plugs and pour
approximately one tablespoon of engine
oil into each cylinder. Grease the spark
plug threads and install the spark plugs.
6. Crank the engine for 3 seconds.
7. Lubricate all cables such as the throttle,
choke, and steering cables.
8. Lubricate the areas of the watercraft
specified under Lubrication points on
page 4-16.

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EJU00946
Fuel system
Draining the fuel system prevents buildup
of varnishes and other harmful deposits that
result when gasoline sits for a prolonged
period of time.
WARNING@Gasoline is highly flammable and explo-
sive. A fire or explosion can cause
severe injury or death. Shut the engine
off. Drain in well-ventilated areas away
from flames or sparks. Do not smoke.
Avoid spilling gasoline. Wipe up spilled
gasoline immediately.
@
To drain the fuel system:
1. Place the fuel cock knob in the “OFF”
position.
2. Drain the fuel tank using a siphon.

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EJU00533
Cleaning the watercraft
Clean the watercraft before storing it for a
long period.
1. Wash down the hull, handlebars, and
drive unit with fresh water.
2. Rinse the engine and bilge area with
fresh water. Drain off all water and wipe
up remaining moisture with clean, dry
rags.
3. Spray the engine’s exterior with a rust
inhibitor and lubricant.
4. Wax the hull with a non-abrasive wax.
5. Wipe all vinyl and rubber components,
such as the engine compartment seals,
with a vinyl protectant.

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EJU00535a
Maintenance and
adjustments
Periodic inspection, adjustment and lubri-
cation will keep your watercraft in the safest
and most efficient condition possible. Safety
is an obligation of the watercraft owner. The
most important points of watercraft inspec-
tion, adjustment and lubrication are
explained on the following pages.
See your Yamaha dealer for genuine
Yamaha replacement parts and optional
accessories designed for your watercraft.
Remember that failures that are the result
of the installation of parts or accessories
which are not qualitatively equivalent to gen-
uine Yamaha parts are not covered by the
limited warranty.
WARNING
●Be sure to turn off the engine when
you perform maintenance unless oth-
erwise specified, otherwise an acci-
dent or injury could result from
unexpected operation, moving parts,
or electric shock. If the owner is not
familiar with watercraft servicing, this
work should be done by a Yamaha
dealer. Improperly serviced compo-
nents could fail or stop operating cor-
rectly, which could result in an
accident.
●Modifications to this watercraft not
approved by Yamaha may cause loss
of performance or excessive noise, or
render it unsafe for use. Consult a
Yamaha dealer before attempting any
changes.

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EJU00552a
Cleaning and adjusting the
spark plugs
The spark plug is an important engine
component and is easy to inspect. The con-
dition of the spark plug can indicate some-
thing about the condition of the engine. For
example, if the center electrode porcelain is
very white, this could indicate an intake air
leak or carburetion problem in that cylinder.
Do not attempt to diagnose any problems
yourself. Have a Yamaha dealer service the
watercraft.
Remove and inspect the spark plug peri-
odically; heat and deposits will cause the
spark plug to slowly break down and erode.
If electrode erosion becomes excessive, or if
carbon and other deposits are excessive,
replace the spark plug with the specified
plug.
Measure the spark plug gap a with a
wire thickness gauge before installing the
spark plug. Adjust the gap to specification if
necessary.
To reinstall spark plug:
1. Clean the gasket surface.
2. Wipe any dirt from the threads of the
spark plug.
3. Screw the spark plug to the correct
torque. Standard spark plug: BR8ES
Spark plug gap:
0.7–0.8 mm (0.028–0.031 in)
Spark plug torque:
25 N·m (2.5 kgf·m, 18 ft·lb)

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EJU00573
Adjusting the carburetor
The carburetor is a vital part of the engine
and requires very sophisticated adjustment.
Most adjusting should be left to a Yamaha
dealer who has the professional knowledge
and experience to perform it. However, the
operator may adjust the trolling speed as
part of the usual maintenance routine.
CAUTION:
The carburetor was set at the Yamaha
factory after many tests. If the settings
are disturbed by someone who does not
have the necessary technical knowledge,
poor engine performance and damage
may result.
EJU00577a
Adjusting the trolling speed
1. Put the watercraft in the water.
2. Start the engine and warm it up for 1 or
2 minutes. Using a diagnostic tachome-
ter or, if necessary, the tachometer in the
multifunction information center, adjust
the engine speed to specification.
3. Turn the throttle stop screw 1 clockwise
to increase engine speed if necessary.
Turn it counterclockwise to decrease
engine speed if necessary.
Trolling speed: 1,250–1,350 r/min

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EJU00588
Specifications
MODEL
ITEMUnit GP800R
WATERCRAFT CAPACITY
Maximum people on board Number of people 2
Maximum load capacity kg (lb) 160 (353)
DIMENSIONS
Length mm (in) 2,930 (115.4)
Width mm (in) 1,150 (45.3)
Height mm (in) 1,020 (40.2)
Dry weight kg (lb) 268 (591)
PERFORMANCE
Maximum output kW (PS) @ r/min 88.2 (120)@ 7,000
Maximum fuel consumption L/h (US gal/h, Imp gal/h) 49.0 (12.9, 10.8)
Cruising range at full throttle hr. 1.2
Trolling speed r/min 1,250–1,350
ENGINE
Engine type 2-stroke
Number of cylinders 2
Engine displacement
cm
3 (cu in)784 (47.8)
Bore & stroke mm (in) 80.0 ×
78.0 (3.15 ×
3.07)
Compression ratio 6.6:1
Lubrication system Variable oil injection
Cooling system Water cooled
Starting system Electric starter
Ignition system Digital CDI
Spark plug BR8ES (NGK)
Spark plug gap mm (in) 0.7–0.8 (0.028–0.031)
Battery capacity V-AH 12-19
Charging system Flywheel magneto
DRIVE UNIT
Propulsion system Jet pump
Jet pump type Axial flow, single stage
Impeller rotation Counterclockwise (viewed from rear)
Transmission Direct drive from engine
Jet thrust nozzle angle Degree 23 + 23
Trim nozzle angle Degree -5, 0, 5, 10, 15
FUEL AND OIL
Recommended fuel Regular unleaded gasoline
Minimum octane rating PON
RON86
90
Recommended engine oil YAMALUBE 2-W, or an equivalent NMMA-
certified TC-W3 marine oil
Fuel tank capacity
Total L (US gal, Imp gal) 60 (15.9, 13.2)
Reserve L (US gal, Imp gal) 10 (2.6, 2.2)
Oil tank capacity L (US gal, Imp gal) 5.5 (1.45, 1.21)

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EJU00595
Troubleshooting
If you have any trouble with your watercraft, use this section to check for the possible
cause.
If you cannot find the cause, or if the procedure for replacement or repair is not described
in this Owner’s/Operator’s Manual, have a Yamaha dealer perform the necessary service.
EJU00596a
Troubleshooting chart
TROUBLE POSSIBLE CAUSE REMEDY PAGE
Engine does not
startStarter motor does not turn over
Engine shut-
off switchClip not in place Install clip
2-8
Fuse Burned out Replace the fuse and
check wiring4-22
Battery Run down Recharge 4-19
Poor terminal connec-
tionsTighten as required
4-19
Terminal corroded Clean 4-5
Starter motor Faulty Have serviced by
Yamaha dealer—
Starter motor turns over
Fuel cock Turned to “OFF” Turn the fuel cock to
“ON”2-7
Fuel Empty Refill as soon as possi-
ble3-3
Stale or contaminated Have serviced by
Yamaha dealer4-10
Fuel tank Water or dirt present Have serviced by
Yamaha dealer4-11
Spark plug Fouled or defective Clean or replace 4-15
Spark plug cap Not connected or loose Connect properly 4-15
Crankcase Filled with water Crank engine with plug
out until clean5-8
Fuel filter Clogged or water
pooledHave serviced by
Yamaha dealer4-11
Choke Choke valve can not be
closed surely by lever
operationHave serviced by
Yamaha dealer —