The Mechanical Equipment Center (MEC) issues snowmobiles. You must attend
a mandatory snowmobile/skidoo maintenance course at the MEC before your
15.1 Snowmobiles in the MEC Inventory
- ELAN (275 lbs): A light-duty, 250 cc, Twin Otter transportable snowmobile
which is not suitable for traverses.
- CHEYENNE (350 lbs): A medium-duty, 503 cc snowmobile which is not
suitable for traverses.
- ALPINE 1 (650 lbs): A heavy-duty, Twin Otter transportable snowmobile.
Available with a 640 cc or 503 cc engine, it is suitable for extensive
traverses and preferred for remote camp work.
- ALPINE 2 (800 lbs), a heavy-duty snowmobile, suitable for remote
camps and traverses.
All snowmobiles have two-stroke engines that require Mogas fuel pre-mixed
with a lubricating oil. The mixture is 50:1 (12 ounces of oil to 5 gallons
of Mogas). Average fuel consumption when pulling a loaded (1,000 pounds)
Nansen sled is approximately 7 miles per gallon.
Park skidoos facing into the prevailing wind and always cover them.
This helps avoid getting snow in the points and accumulating snow under
the snowmobile's cowling.
15.2 Snowmobile Troubleshooting
15.2a Fuel Flow Problems
Symptoms: Engine cranks but won't run, no fuel present in line
from pump to carb. Engine may run briefly after priming.
Diagnosis and Cure:
15.2b Starter and/or Cranking Problems
- Check fuel level in tank.
- Pry fuel line off carb, pressurize the fuel tank (seal and blow into
the vent line) to see if fuel flows out of the end of fuel line. Crank
engine and see if fuel pulses out of the end of the fuel line.
- If fuel flows and then pumps OK, the problem was probably just small
ice crystals in the fuel pump valves. Pressurizing the tank dislodged
them, thus solving the problem. Replace the line and go.
- If fuel flows when pressurized but does not pump, the problem is fuel-pump-related.
First disconnect the vacuum pulsation line from the center of the fuel
pump to the engine crankcase. Blow through the line -- if blocked, clean
ice out of the line with a wire. Check the nipples on the pump and crankcase
for obstructions. If the vacuum line is clear but fuel still does not
pump, replace the pump or remove it and let it thaw.
- If fuel will neither pump or flow, then either the fuel line or the
fuel filter is clogged. Clean the fuel line or replace the filter.
- If the tank is under vacuum when you open the filler, check the vent
line for obstructions or pinches. Occasionally the line will rub against
the exhaust, melting the vent hose. Make sure the tank is venting properly.
- If all of the above steps have been tried and still no fuel flows,
check the fuel line for cracks or holes, and look for any obvious fuel
leaks (i.e., discolored snow) in the engine compartment. Repair or replace
the fuel line.
- A mixture of 30 mL of isopropyl alcohol per 5 gallons of pre-mixed
Mogas will lessen the chance of water contamination and fuel icing.
- Pouring fuel through a trail flag or rag placed over a funnel will
help eliminate any snow contamination of the tank and will filter the
Symptoms: Engine cranks slowly or not at all when key is turned.
Diagnosis and Cure:
15.2c Spark Problems
- Usually this problem indicates a dead battery, and requires pull-starting
the engine. The battery can be charged with an A.C. charger; however,
it should charge on its own with skidoo usage, unless the battery is
shorted or the rectifier is faulty.
- If the battery is fine, check the in-line fuse (30 amp) in the red
wire near the starter, or see if the red-green wire has slipped off
the terminal on the starter solenoid. Finally, the starter itself may
- The recoil (pull) starter should be used when the engine is cold,
so the electric starter is not overtaxed.
Symptoms: Engine cranks but won't start. Fuel is present in the
line between fuel tank and carb.
Diagnosis and Cure:
Unhook both spark plugs, push the spare plugs in the wire caps, ground
the metal plug bodies to the metal engine housing, and crank the engine.
If a spark can be seen at the electrode of the spare plugs, the problem
may be that the installed plugs were fouled with excessive fuel, ice,
or a piece of carbon. Install new plugs or clean the existing ones. When
the engine is cold, the spark may be hard to see in direct sunlight.
Caution: Do not remove spark plugs for this test. If you have a spark
and the crankcase is full of fuel, a fire could start.
If a spark is not present, the problem is in the electrical system rather
than spark plugs. First, check the kill switches and all electrical connectors.
If they check out OK, the solution of the problem depends on the engine
640 cc Engine: Problem is probably ice in the points (this mostly occurs
after exposure to blowing snow). Remove rewind starter and starter pulley,
rotate magneto housing until upper point set is visible, spray with alcohol,
scrape with file, spray with WD-40, repeat for lower point set, and reassemble.
503 cc Engine: Electronic ignition -- problem is probably the igniter
Either engine: Still no spark -- may be a bad coil or a shorted wire.
15.2d Power Problems
Symptoms: Runs but lacks power.
Diagnosis and Cure:
If the engine seems to be running fine, but the skidoo has trouble with
uphill starts, the problem may be with the clutch-driven pulley. Remove
the cowling and see where the belt is riding on the pulley. The belt should
be along the outer edge of the driven pulley when the skidoo is at rest.
If the belt is instead slotted down between the driven pulley halves,
lubricate the driven pulley shaft, taking care not to lubricate the pulley
faces, shift transmission into neutral, and alternately rev engine and
apply brake until the belt works its way to the outer edge.
If the engine has very low power or dies when revved, remove the carb
and check for ice. If ice is present, thaw out carb and reinstall. If
the engine is weak and running rough, but the carb is ice-free, the problem
may be a bad spark in one cylinder. Follow the procedures outlined above
for cleaning/replacing spark plugs.
Altitude Adjustment: Assess mixture by hill climbing performance
and spark plug color. Chocolate brown is correct; gray or white is too
lean, while black is too rich. From sea level to 4,000 feet decrease the
jet size by one increment from standard setting (i.e., 290 to 280):
At 4,000 feet to 6,000 feet decrease by two increments.
At 8,000 to 11,000 feet decrease by four increments.
Remember to richen up the mixture when returning to lower altitudes,
under penalty of blown-up engines.
15.2e Track/Suspension Problems
Symptoms: Machine pulls to one side.
Diagnosis and Cure:
Check for loose or broken bogie sets.
Each operator should be made responsible for checking their machine
- Daily: Check suspension, particularly when on glacier ice or sea ice.
Look for broken bogie sets. Check general operations on vehicle. Make
sure bogie bungy is in place.
- Weekly: Check for loose mounting bolts on bogies, skis (particularly
the two bolts through the spring), rear suspension and steering (especially
the two nuts on the transmission case). A small suspension problem can
rapidly get bigger (slashed tracks, broken bogie mounts, etc.).
Keep an eye on the track's adjustment. Keep the track centered between
link plates. Watch track tension -- there should be a distance of 1-3/4"
(this equals 2nd two joints of your 3rd finger) from track above bogies
to frame edge below forward end of rail.
Beware of loose trailing straps and ropes; they can get entangled in
the tracks and around axles.
Be kind to transmissions and shift gently. If gear(s) will not engage,
turn off motor, shift gears and restart. Abusive shifting can cause drive
train problems that are not repairable in the field. Never shift the transmission
unless the snowmobile is stopped.
Note: LC-130 transport can result in skidoo damage either from abuse
or during loading. Supervise the loading and inspect your machines as
much as possible.
Many thanks to Dr. Bill McIntosh for his invaluable input.
Chapter 16: Sea Ice