Snowmobile Polaris (2006 year). Instruction - part 23

 

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Snowmobile Polaris (2006 year). Instruction - part 23

 

 

4.2

CARBURETION

WARNINGS

WARNINGS

When ever servicing the carburetor or fuel 
system, it is important to heed the following 
warnings.

GENERAL INFORMATION

SERVICE PRECAUTIONS

In order to perform service work efficiently and to prevent 
costly errors, the technician should read the text in this 

manual, thoroughly familiarizing him/herself with procedures 
before beginning. Photographs and illustrations have been 
included with the text as an aid. Notes, cautions and warnings 
have also been included for clarification of text and safety 
concerns. However, a knowledge of mechanical theory, tool 
use and shop procedures is necessary to perform the service 
work safely and satisfactorily. Use only genuine Polaris 
service parts.

Cleanliness of parts and tools as well as the work area is of 
primary importance. Dirt and foreign matter will act as an 
abrasive and cause damage to precision parts. Clean the 
snowmobile before beginning service. Clean new parts before 
installing.

Watch for sharp edges which can cause personal injury, 
particularly in the area of the tunnel. Protect hands with 
gloves when working with sharp components.

If difficulty is encountered in removing or installing a 
component, look to see if a cause for the difficulty can be 
found. If it is necessary to tap the part into place, use a soft 
face hammer and tap lightly.

Some of the fasteners in the snowmobile were installed with 
locking agents. Use of impact drivers or wrenches will help 
avoid damage to fasteners.

Always follow torque specifications as outlined throughout 
this manual. Incorrect torquing may lead to serious machine 
damage or, as in the case of steering components, can result in 
injury or death for the rider(s).

If a torquing sequence is indicated for nuts, bolts or screws, 
start all fasteners in their holes and hand tighten. Then, 
following the method and sequence indicated in this manual, 
tighten evenly to the specified torque value. When removing 
nuts, bolts or screws from a part with several fasteners, loosen 
them all about 1/4 turn before removing them.

If the condition of any gasket or O-Ring is in question, replace 
it with a new one. Be sure the mating surfaces around the 
gasket are clean and smooth in order to avoid leaks.

Some procedures will require removal of retaining rings or 
clips. Because removal weakens and deforms these parts, they 
should always be replaced with new parts. When installing 
new retaining rings and clips use care not to expand or 
compress them beyond what is required for installation.

Because removal damages seals, replace any oil or grease 
seals removed with new parts.

WARNING

Always stop the engine and refuel outdoors or in a well 

ventilated area

WARNING

Do not smoke or allow open flames or sparks in or near 

the area where refueling is performed or where gaso-

line is stored or used.

WARNING

Do not overfill the tank. Do not fill the tank neck.

WARNING

If you get gasoline in your eyes or if you swallow gaso-

line, see your doctor immediately.

WARNING

If you spill gasoline on your skin or clothing, immediate-

ly wash it off with soap and water and change clothing.

WARNING

Never start the engine or let it run in an enclosed area. 

Gasoline powered engine exhaust fumes are poison-

ous and can cause loss of consciousness and death in 

a short time.

4.3

CARBURETION

Polaris recommends the use of Polaris lubricants and greases, 
which have been specially formulated for the top performance 
and best protection of our machines. In some applications, 
such as the engine, warranty coverage may become void if 
other brands are substituted.

Grease should be cleaned from parts and fresh grease applied 
before reassembly of components. Deteriorating grease loses 
lubricity and may contain abrasive foreign matter.

Whenever removing or reinstalling batteries, care should be 
taken to avoid the possibility of explosion resulting in serious 
burns. Always disconnect the negative (black) cable first and 
reconnect it last. Battery electrolyte contains sulfuric acid and 
is poisonous! Serious burns can result from contact with the 
skin, eyes or clothing. ANTIDOTE: External - Flush with 
water. Internal - Drink large quantities or water or milk. 
Follow with milk of magnesia, beaten egg, or vegetable oil. 

Call physician immediately. Eyes - Flush with water for 15 
minutes and get prompt medical attention.

GASOLINE VOTALITIY

See “GASOLINE VOLATILITY” on page 2.9.

2 STROKE GASOLINE / OIL PRE MIX 

see “2 STROKE GASOLINE / OIL PRE MIX” on page 2.10

FUEL DELIVERY SYSTEM 
(Carbureted)

CARBURETED SYSTEM OVERVIEW

The carbureted fuel system contains many components which 
directly affect fuel mixture and drive ability. When performing 
diagnosis or carburetor maintenance, the entire fuel delivery 
system should be inspected. The illustration above shows parts 
of the system requiring periodic maintenance to ensure there is 
no fuel or air leaks present.

Fuel filters should be replaced at least once per season. More 
often if any contamination is suspected.

Fuel lines should be replaced every other season. More often if 
they become brittle or swollen. Fittings should be inspected 
for cracks or leaks. Do not use pliers or other tools that may 
damage fuel lines when installing or removing fuel lines.

Test run and check the fuel system for leaks any time parts are 
replaced. Verify that all lines are routed correctly and away 
from any moving parts.

NOTE:  Some models use fuel filters that are located 
inside the fuel tank. To inspect/replace filter, remove 
fuel cap and use a long clean wire, bend one end in a 
hook shape. Pull the fuel line that is in the tank up 
through the filler hole. Inspect filter on end of fuel 
pick up line. Replace if worn or clogged.

Red fuel line is the exterior line for outside the tank. The violet 
line is the interior line for inside the fuel tank. They cannot be 
interchanged! The violet line used inside the tank will fade and 
turn clear after a relatively short time. This does not affect the 
function or durability of the line.

4.4

CARBURETION

When replacing fuel line, be sure to use the correct color line 
for inside or outside the fuel tank. Also, be very careful not to 
bend fuel line to a point of kinking it. If it becomes kinked, it 
must be replaced. Always inspect fuel lines when replacing, or 
if carbs, carburetor racks, or fuel pumps are removed from 
chassis.

FUEL PUMP (non-injected units)

FUEL PUMP OVERVIEW

The fuel pumps (340/550 style shown). The differences are in 
the size and location of the pumps. Pumps may be mounted to 
the engine, air/oil box or to the chassis.

In the two cycle engine, the pressure in the crankcase changes 
with the up and down stroke of the piston. The amplitudes of 
pressure vary according to the RPM and degree of throttle 

4.5

CARBURETION

opening. Whether idling or at full throttle, the pressure built up 
in the crankcase has enough amplitude to operate the pump.

When the piston is on the upstroke, crankcase pressure in that 
cylinder becomes less positive. The diaphragm in the fuel 
pump moves toward the engine, causing a negative pressure or 
suction in the pump chamber. This causes the inlet valve from 
the fuel supply to open and permits fuel to enter the chamber. 
This same suction causes the outlet valve (to the carburetor) to 
close so that fuel cannot return form the carburetor.

When the piston begins its downward stroke, the pressure 
from the crankcase becomes positive, causing the fuel pump 
diaphragm to move in the opposite direction and reversing the 
pressure in the fuel pump chamber. This causes the inlet valve 
in the pump to close and the outlet valve to open, filling the 
float bowl in the carburetor. When the float level in the 
carburetor reaches its standard level, the needle valve will 
close, preventing more fuel from entering the carburetor, even 
though the fuel pump continues to try to provide the carburetor 
with fuel.

MAINTENANCE

The impulse operated diaphragm fuel pump does not require 
any specific scheduled maintenance. However, the following 
procedures should be observed.

OPERATION

The pump may be checked for operation by removing the fuel 
supply line from the carburetor and placing it into a container. 
With the engine idling at approximately 2000 RPM, a steady 
flow of fuel should be visible.

CLEANING

The pump and impulse line must be disassembled and cleaned 
of foreign material in the event of piston or other internal 
engine part failures which produce fragments.

INSPECTION

Disconnect impulse line from pump. Connect a Mity Vac to 
impulse fitting (or line) and apply 4-6 PSI pressure. 
Diaphragm should hold pressure indefinitely.

The diaphragms and check valves must be carefully examined 
for cracks, holes, or other damage. If in doubt as to the 
condition of any internal parts, replace all diaphragms, check 
valves, and gaskets.

MIKUNI JET NEEDLE 

OVERVIEW

This needle (example) is a 
9DH01-57. The first number 
is the approximate overall 
length in 10mm increments of 
the jet needle. The 9 indicates 
the needle is approximately 
90mm but less that 100mm in 
length. 

The letters on the jet needle 
indicate the angle of both 
tapers. The first letter 
designates the taper angle of 
the top section (closest to the 
grooves) and the second letter 
designates the angle of the 
bottom taper. The taper 
angles are graduated in 15' 
(15 minute) increments. The 
jet needle marked 9DH01-57 
would have a top taper of 1_0' 
and a bottom taper of 2_0'. 

The number following the 
letters on the jet needle is the 
serial number and it varies 
with individual jet needles. 

The last number, 57 indicates 
that the outside diameter is 
2.57mm. The smaller the O.D., the richer the mixture.

Table 4-1: Mikuni Jet Needle

DESIGNATOR

DESCRIPTION

9

Overall length in 10mm increments

D

Taper of the top section of the needle

H

taper of the bottom section of the 
needle

01

Serial number

-57

Outside diameter (O.D.) of the 
straight portion

 

 

 

 

 

 

 

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