Snow Break In

Before starting your sled please do the following:

  • NEVER USE DRY GAS IN A TANK THAT FUELS A 2 STROKE-CYCLE ENGINE. NEVER.
  • Even dry gas that reads “safe for two cycle” will lean the fuel mixture caused by the alchohol.
  • If there is water in your tank get rid of it and flush the fuel system before running the motor.
  • Before starting your overhauled snowmobile engine please do the following: mix oil with the fuel at 50/1 with an oil injected motor and double manufactures recommendation for normal use on premix sleds/ for the 1st 10 hrs of operation.
  • Use 89 octane unless the compression ratio has been increased and/or the manufacturer states otherwise.
  • Start your engine at home base to verify that it actually does start.
  • Do not run the engine any longer than it takes for it to reach normal operating temperature and never ride the snowmobile or rev the engine above 4,000 rpm’s no matter what until the engine has reached normal operating temperature, never. Now you may go for a ride (one up and not towing).
  • Do not exceed 3/4 throttle when riding for the first 2 hrs. And vary the speed from idle until you have two hours on the engine.
  • It is time consuming and tedious but it is the basis for long and happy engine life.
  • At this point (after 2 hrs.) You can ride the sled periodically giving it short runs (up to 20 seconds) up to full throttle.
  • This should continue until there 4hrs hours total (approx.) On the engine, and then your powerhead should be broken in allowing you to now and only now use it for the intent and purpose of design.
  • If you follow the outlined procedures you will get better service from your engine. Be sure that at maximum throttle the engine will turn up to its proper wide open rpm, the top operating rpm for your snowmobile is found listed in your owners manual.
  • If the sled doesn’t achieve or it goes over the specified maximum R.P.M., the engine can become damaged almost immediately so shut it off and call us.
  • The wrong clutch components/adjustments and or fuel jets and or other variables can cause the motor to lug, overheat or at the other extreme over rev and destroy all our good work.
  • Never run the sled when it is out of its intended elevation, temperature, or snow conditions.
  • Be sure to bring the motor to me for the re-torque of the cylinder head bolts if required (no charge).

Snowmobile engine overheating

Liquid cooled Snowmobile engines generally operate normally at temperatures below 175 degrees. The thermostat opens at 120 degrees.  Most temperature lights come on at around 180 degrees indicating an overheat condition will result if operation is not ceased. Most gauges have the hot area begin at 170.

If the snowmobile is operated above the boiling point of the coolant, the coolant will expel through the overflow. Ethel glycol/green antifreeze coolant will boil at

Full strength 388 degrees,

when mixed at a ratio of 70% coolant 30% water it boils at 235 degrees. 50/50 boils at 223

140… warm

160… hot…

180… too hot shut off

Preventing overheating a liquid cooled snowmobile.

Outside temp below 30 degrees

Snow Flap should be ideally less than 3 inches from the trail with rider on sled

Ride only on surface that has loose snow that can contact heat exchangers

Ice scratchers properly installed

Coolant full with a minimum of 50% coolant and pressure cap on correctly

No cooling system leaks

Clean carbs, jetted properly and quality fuel

Quality 2 stroke oil in fuel or injection tank

Do not over rev the engine

Shut off engine if temperature light comes on or gauge reads hot

O’Connor and Sons recommends that a properly trained technician (us) service your motor. If you elect to do it yourself, be sure to use caution, common sense, and to observe all safety procedures in the vicinity of gasoline, moving engine parts, high temperature components, heavy items, and electrical or ignition systems.

The information offered here or over the phone is often only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications.  Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation or a technique, enlist our services as professionally trained technicians.