TOHATSU MD 25B2 JET User manual

OWNER'S
MANUAL
MD 25B2 JET
35B2 JET
Supplement
No.003-11095-1
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GENERAL INFORMATION ......................................................................2
Before Operating Your Outboard ...................................................................................................... .2
Specications .......................................................................................................................................3
Components .........................................................................................................................................4
OPERATION .............................................................................................5
How the Jet Drive Operates .................................................................................................................5
Stopping the Boat in an Emergency ................................................................................................... .6
Steering the Boat ................................................................................................................................ .6
Mooring e Boat ................................................................................................................................7
Water Intake Blockage ...................................................................................................................... .8
Clearing A Lodged Impeller .............................................................................................................. .8
Lubricating the Driveshaft Bearing .....................................................................................................9
Operating In Freezing Temperatures ...................................................................................................9
Pre-Starting Check List .......................................................................................................................9
Operating In Salt Water Or Polluted Water ......................................................................................10
Operating In Shallow Water ..............................................................................................................10
MAINTENANCE ...................................................................................... 11
Impeller Removal and Installation ....................................................................................................11
Worn/Dull Impeller ...........................................................................................................................13
Steering Pull Adjustment ...................................................................................................................13
Impeller Clearance Adjustment .........................................................................................................13
Replaceable Jet Drive Shear Key ........................................................................................................14
Shift Cable Adjustment......................................................................................................................15
Corrosion Control Anode ..................................................................................................................17
Lubricating the Driveshaft Bearing ...................................................................................................17
TROUBLESHOOTING ............................................................................19
Engine Over-Speed (Excessive RPM) ................................................................................................19
Performance Loss ...............................................................................................................................19
ENGINE INSTALLATION .......................................................................20
Transom height of the boat .............................................................................................................. .20
Locate center line of the outboard ................................................................................................... .20
Determining the Mounting Height of the Outboard ........................................................................21
Water Testing ................................................................................................................................... .22
Index
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GENERAL INFORMATION
Before Operating Your Outboard
Read this manual carefully. Learn the dierence in handling characteristics between a jet drive
boat and a propeller driven boat. If you have any questions, contact your dealer.
STEERING AT LOW SPEEDS
Unlike propeller driven boats, the jet drive boat tends to lose steering control as less water is drawn
in and expelled. Increase speed slightly to regain steering.
MANEUVERABILITY
e jet drive is highly maneuverable at higher speeds, more so, than propeller driven boats. Use
caution when turning to prevent spin - outs.
IN NEUTRAL
e impeller will continue to rotate while the engine is in neutral. Although the approximate
balancing of forward and reverse thrust will minimize boat movement, the boat may tend to move
slowly forward or backward. is is normal for a direct - drive jet driven boat. e operator should
be aware of this and use caution whenever the engine is running.
Safety and operating information that is practiced, along with using good common sense, can
help prevent personal injury and product damage.
is manual as well as safety labels posted on the outboard use the following safety alerts1. to
draw your attention to special safety instructions that should be followed.
DANGER
Indicates a hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING
Indicates a hazardous situation which, if not avoided, could result in death or
serious injury.
2
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Watch for boat movement in neutral. When the jet drive is in neutral, the drive impeller
continues to rotate. Although the approximate balancing of forward and reverse thrust will
minimize boat movement, the boat may tend to move slowly forward or backward. is is normal
for a direct - drive jet driven boat. e operator should be aware of this and use caution whenever
the engine is running.
Specifications
Owner’s manual requires the correction. Please replace specication with below specication.
GENERAL INFORMATION
MODEL MD 25B2 JET MD 35B2 JET
Overall Lengh, in/mm EPO 23.6/600 EFO 44.1/1120
Overall Width, in/mm EPO 13.6/345 EFO 15.1/384
Overall Height, in/mm 42.2/1,072
Recommended Transom
Height, in/mm 22.6/573
Weight, lbs/kg EPO 196.2/89 EFO 202.8/92
Output Jet power, PS/kW 25/18.4 35/25.7
Horsepower, PS/kW
40/29.4 50/36.8
Max, Operating Range 5,150 - 5,850
Number of Cylinders 3
Piston Displacement, Cu in/cc
42.5/697
Bore × Stroke, in/mm 2.68×2.52/68×64
Exhaust System Jet Exhaust
Lubrication System Oil injection
Cooling System Water cooling
Starting System Electric starter motor
Ignition Inductive Ignition
Spark Plugs NGK IZFR6Q
Alternator V . W 12V - 280W 23A
Trim Stages 4
Grease Driveshaft Bearing 3HT-65319-0
Fuel
Unleaded regular gasoline : Pump posted 87 Octane
(research octane rating of 91)
Gear Reduction Ratio 1 : 1
Emission Control System DI, EC (Electronic enigine Control)
2
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Components
ab
c
d
e
fg
h
i
j
kl
m
no
p
a
d
fg
hij
kl
n
OPERATION
M25 Jet Drive
a Top Cowl
b rottle Grip
c Stop Switch Lanyard
d Reverse Lock lever
e Shift Cable
f Drive Shaft Housing
g rust Rod
h Water Outlet
i Jet Drive Housing
j Battery Cable
k Reverse Gate
l Water Intake Housing
m Shift Lever
n Fuel Connecter
o Stop Switch
p Main Switch
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How the Jet Drive Operates
A jet driven boat has substantially dierent handling characteristics compared to a propeller
driven boat. It is recommended that the operator adjusts to these characteristics by experimenting
in open water at both high and low speeds. e driveshaft driven impeller draws water up through
the water intake and then redirects it at a high pressure through the water outlet nozzle to create
forward thrust. To obtain reverse, the reverse gate moves over the outlet nozzle to direct the water
in the opposite direction.
a
c
b
a - Water intake
b - Water outlet nozzle
c - Reverse gate
When the jet drive is in neutral, the impeller continues to rotate. However, the reverse gate is
positioned so that some of the forward thrust is diverted to create reverse thrust. is approximate
balancing of forward and reverse thrust will minimize any boat movement. Because the impeller
is always rotating and creating thrust when the engine is running, the boat may tend to move
slowly forward or backward. is is normal for a direct-drive jet driven boat. e operator should
be aware of this and use caution whenever the engine is running.
OPERATION
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WARNING
Avoid injury resulting from contacting the rotating impeller or having hair,
clothing, or loose objects drawn into the water intake and wrapping around
the impeller shaft. Stay away from the water intake and never insert an object
into the water intake or water outlet nozzle when the engine is running.
The jet drive is always drawing water into the housing when the engine is
running. Do not operate the jet drive with the grate removed from the water
intake. Keep hands, feet, hair, loose clothing, life jackets, etc., away from
the water intake. Never insert an object into the water intake or water outlet
nozzle when the engine is running.
Stopping the Boat in an Emergency
A jet powered boat has emergency stopping capability unique to this form of propulsion.
WARNING
Using the emergency stopping capability of a jet drive unit will slow down the
boat in an emergency. However, sudden stopping may cause the occupants
of the boat to be thrown forward or out of the boat resulting in serious injury
or death. Use caution when performing the emergency stopping procedure,
and be sure to practice in a safe area.
In an emergency, putting the jet outboard into reverse and applying reverse
throttle can rapidly slow down the boat and reduce stopping distance.
However, such a maneuver may cause occupants in the boat to be thrown
forward or possibly out of the boat.
Steering the Boat
e jet drive is dependent on water jet thrust for steering the boat. If the water jet thrust should
ever stop (water blockage, engine stops, etc.), the boat will slow to a stop. However, while slowing
there will be a reduced ability to steer the boat.
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WARNING
Steering the vessel in a tight turn can result in loss of boat control. In some
cases, the boat can spin out or roll over, causing serious injury or death. Avoid
steering beyond the capabilities of the vessel, especially at high speeds.
WARNING
A loss or reduction in water jet thrust will directly affect boat directional control,
and may result in property damage, personal injury, or death. Boat directional
control can also be substantially reduced or lost altogether by a sudden loss
of power such as running out of gas, quickly backing off the throttle, turning
off the ignition switch, activating the lanyard stop switch, or plugging the
water intake to the jet pump. Use caution when maneuvering at high speeds
in areas where debris (weeds, logs, gravel, etc.) could be picked up into the
jet drive. The ability to take evasive action is dependent on sufficient water jet
thrust to control the boat.
While steering the boat at engine speeds above idle, the boat will respond
quickly; but, due to the relatively flat-bottom hulls and lack of a gearcase in
the water, the boat will tend to skid on turns. Turns must be started early and
use sufficient power to maintain steeringcontrol.
Mooring The Boat
Be sure to tilt the jet drive out of the water when the boat is pulled onto a beach or tied to a dock
in shallow water. Failure to do this may cause the water intake housing to ll with sand or debris
and could prevent the outboard from cranking over for starting.
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Water Intake Blockage
WARNING
A rotating impeller could cause injury if contact is made with hands, clothing,
or tools. To avoid injury, keep hands and clothing away from the inlet or outlet
of the jetdrive, regardless of whether the boat is in the water. Secure tools
and loose items to avoid being struck by projectiles as a result of contact with
the rotating impeller, and to prevent damage to the impeller.
A large amount of debris being drawn into the water intake may result in a
loss of power. Intake suction holding debris against the grate will result in
restricted water flow. Shutting the engine off may allow the debris to fall off
the intake grate allowing full power to be restored. If debris does not fall off
the intake grate, the engine must be shut off and debris physically removed
from the grate.
Clearing A Lodged Impeller
WARNING
Rotating the flywheel to free a lodged impeller can accidentally start the
engine, resulting in serious injury or death. Always turn the ignition key or
lanyard stop switch to the “OFF” position and remove all spark plug leads
from the spark plugs.
It is possible for debris to lodge between the impeller and jet housing wall,
especially after the engine has been stopped. This will lock the driveshaft and
will prevent the engine from being able to crank over for starting. Following
are steps for dislodging the impeller.
1. Position lanyard stop switch to the “OFF” position.
2. Remove spark plug leads to prevent the engine from accidentally starting.
3. Remove flywheel or rewind cover and rotate the engine flywheel
counterclockwise.
If this does not dislodge the impeller, it will be necessary to remove the six screws and water intake
housing.
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Lubricating the Driveshaft Bearing
Before each use, lubricate the driveshaft bearing. Refer to Maintenance - Lubricating the
Driveshaft Bearing.
Operating In Freezing Temperatures
If there is a chance of ice forming on the water, the jet drive should be raised out of the water and
drained completely of water. If ice should form at the water level inside the outboard driveshaft
housing, it will block water ow to the engine causing possible damage. Do not start the engine
until the ice is clear.
Pre-Starting Check List
• Operator knows safe navigation, boating, and operating procedures.
• An approved personal otation device of suitable size for each person aboard and readily
accessible (it is the law).
• A ring type life buoy or buoyant cushion designed to be thrown to a person in the water.
• Know your boats maximum load capacity. Look at the boat capacity plate.
• Fuel supply OK.
• Ensure the boat drain plug is installed.
• Arrange passengers and load in the boat so the weight is distributed evenly and everyone is
seated in a proper seat.
• Tell someone where you are going and when you expect to return.
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• Know the waters and area you will be boating; tides, currents, sand bars, rocks, and other
hazards.
• Check steering for free operation.
• Check for debris around the rudder and reverse gate which may jam or hinder operation.
• Before launching, examine the jet drive water intake for obstructions which may prevent
pumping of water.
• Ensure the driveshaft bearing on the jet drive is lubricated.
Operating In Salt Water Or Polluted Water
If the boat is kept moored in the water, always tilt the outboard so the water intake is completely
out of water when not in use.
Wash down the outboard exterior and ush out the exhaust outlet of the jet drive with fresh water
after each use.
When used in salt water more than in fresh water, remove mounting hardware, grease, and
reassemble once a year. Failure to do this may result in hardware that is dicult if not impossible
to remove at a later date.
Operating In Shallow Water
e life of the impeller and water intake can be greatly increased by avoiding the intake of sand
and gravel. e intake suction will act like a dredge when the water intake comes close to the
bottom. It is better to stop the engine and drift up to shore when landing, and to shove o with
an oar when leaving. e engine can idle through areas of water less than 61 cm (2 ft.) deep, but
there should be more than 61 cm (2 ft.) of water under the boat when increasing speed to reach
full plane.
Once the boat is on plane, the boat speed will prevent the ingestion of gravel and other debris
from the bottom. e suction is still present, but the water intake passes too quickly over the
bottom to allow debris to be drawn into the water intake.
When boating through shallow water areas, choose a course of travel that avoids sharp rocks and
other underwater obstacles that could damage the boat. Running the boat through these areas on
full plane may be helpful as the boat will be riding higher in the water. If the boat gets stuck on
the bottom, immediately stop the engine and move the boat to deeper water.
MAINTENANCE
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Impeller Removal and Installation
WARNING
Rotating the driveshaft may cause the engine to crank over and start. To
prevent this type of accidental engine starting and possible serious injury
caused from being struck by a rotating impeller, always turn the ignition key
or lanyard stop switch to the “OFF” position and remove the spark plug leads
from the spark plugs while servicing the impeller.
1. Position the key switch or lanyard stop switch to the “OFF” position.
2. Remove the spark plug leads to prevent the engine from starting.
3. Remove the six screws securing the water intake housing, and remove the
water intake housing.
MAINTENANCE
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4. Straighten the bent tabs on the impeller nut retainer and remove the impeller
nut.
a - Tabs b - Impeller nut
5 . Pull the impeller straight off the shaft.
If the impeller is tight, use a hammer and a block of wood to rotate the impeller clockwise on the
shaft until the keyway is directly above the at on the shaft. is will free the jammed key and
allow removal.
ba
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Worn/Dull Impeller
e intake of gravel through the pump can round o and wear the leading edges of the impeller.
Some conditions that could be experienced from a worn/dull impeller are as follows:
• Noticeable performance loss, especially on acceleration
• Diculty getting the boat on plane
• An increase in engine RPM at wide open throttle
IMPORTANT : Do not sharpen or alter the top side lifting angle. Check the impeller
blades occasionally for damage. Use a at le to resharpen the leading
edges. Sharpen to a 0.8 mm (1/32 in.) radius by removing material from
bottom side only.
Steering Pull Adjustment
e steering on some boats will have the tendency to pull
towards starboard. is pulling condition can be corrected by
using a pliers and bending the ends of the exhaust ns 1/16 in.
(1.5mm) toward the starboard side of the outboard.
Impeller Clearance Adjustment
e impeller should be adjusted so there is approximately 0.8 mm (0.031 in.) clearance between
the impeller edge and liner. Operating the jet drive in waters that contain sand and gravel can
cause wear to the impeller blades, and the clearance will start to exceed 0.8 mm (0.031 in.).
a - Exhaust fin
b
a
a - Leading edge
b - Top side lifting angle
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As the blades wear, shims located in the stack outside of the impeller can be transferred behind the
impeller. is will move the impeller further down into the tapered liner to reduce the clearance.
a - Shims
b - Clearance between impeller edge and liner
Check the impeller clearance by sliding a feeler gauge through the intake grate and measure
the clearance between the impeller edge and liner. If adjustment is required, refer to Impeller
Removal and Installation.
Replaceable Jet Drive Shear Key
e jet drive is equipped with a shear key to protect it in the event of a lodged impeller. e shear
key can be reached by removing the water intake housing and impeller. Grease the drive shaft,
shear key, and impeller bore when replace these parts. Refer to Maintenance-Impeller Removal
and Installation.
a
b
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Shift Cable Adjustment
WARNING
Pressurized water hitting the reverse gate may cause it to engage, causing
sudden and unexpected slowing of the boat. This can cause serious injury or
death from occupants being thrown within or out of the boat. Adjust the shift
link rod to lock the reverse gate, preventing it from interfering with water flow.
CHECKING SHIFT LINK ROD ADJUSTMENT
Check the shift link rod adjustment in forward shift position. e correct adjustment will position the
shift cam far enough on the roller in order to lock the reverse gate into forward position. e reverse
gate should not be able to be forced up towards neutral. Pull on the reverse gate by hand to verify.
a
b
c
d
ea
b
cd
d
F type P type
a - Shift cable
b - Shift cam
c - Roller
d - Reverse gate e - Ball end
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1. Place roller at bottom of shift cam groove as shown.
Correct Incorrect
2. Place the shift lever and shift cam into full forward position.
3. Bring groove A to position B and secure the part.
B
A
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4. Attach ball end to shift cable, align the hole as shown, and secure the part.
5. The reverse gate should not be able to be forced up towards neutral.
Pull on the reverse gate by hand to verify.
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Corrosion Control Anode
An anode helps protect the outboard against galvanic corrosion by sacricing its metal to be
slowly corroded instead of the outboard metals.
An anode is located on the water intake housing. An anode requires periodic inspection, especially
in salt water which will accelerate the erosion. To maintain this corrosion protection, always
replace the anode before it is completely eroded. Never paint or apply a protective coating on the
anode as this will reduce eectiveness of the anode.
a - Water intake housing anode
Lubricating the Driveshaft Bearing
Lubricate the driveshaft bearing before each use.
Description Where to used Part No.
Grease Drive shaft bearing 3HT-72309-0
Grease Gun Drive shaft bearing 3HT-65324-0
IMPORTANT : It is important not to use a general all purpose grease for this bearing.
e lubricant recommended is a water resistant grease of the proper
consistency for this application. If a substitute is used, be sure that it is
water resistant and of the same consistency.
a
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