Rotax Owner.com Education, Information, Support

What oil should I use?
My oil level is always low, where is it going?
Gearbox additives; are they important?
Should I use an oil thermostat?
What oil hose should I use?
I heard that the oil change is complicated, is this true?
First start up, what do I do?
Fire-Sleeve information

Fuel related:

What fuel do I use?
Can I use car gas?
Can I use Avgas?
What about ethanol?

Ignition related:

Does the ignition system need a battery to run the engine?
I have a bad mag drop, what do I do?
How does the electronic ignition work?

Gearbox related:

what does the clutch do?
Slipping torque; same as friction torque?
What are Dogs?
Friction torque, what is it and why is it so important?

General:

Sprag clutch - What is it?
Good operating practices
Frequent oil changes
What gear ratio do I have?
Why does my tach needle jump around?
Is the 912/914 series engine reliable?
Do the 912/914 engines reach TBO?
How do I go “on-condition”
What is the warranty for the 912/914?
My oil pump leaks, what should I do?
Where is the mixture control?
My 912S does not start, what’s going on?
What is the difference between a 912 and a 912S?

OIL related:

What oil should I use?
We recommend Mobil MX4T. If you use more than 30% Avgas use semi-synthetic oil as it captures lead better. For more info see SI-912-016.
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My oil level is always low, where is it going?
Oil will “hide” in the crankcase; you must return this oil back to the oil tank before checking the dipstick. Follow instructions in section 10.3.3 of the Operator’s Manual or SI-27-1997 “Oil level check”
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Gearbox additives; are they important?
Gearbox additives are important as the gearbox is lubricated by the engine oil, just like a modern motorcycle engine, but, there are some caveats:
• Premium quality car oils protect the gears just about as well at half the price.
• More is not necessarily better; having a larger amount of gearbox additives (mostly zinc) is shown to actually decrease the oils ability to protect the gears.
• Good operating practices and frequent oil changes have more effect on gear wear than the presence of gear additives.
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Should I use an oil thermostat?
An oil thermostat (stat) is useful for quicker warm-ups and to keep operating temps up in cold weather. Field reports have been very positive. See SL-912-011 for more information.
• Caution must be used during installation of the stat and during oil system maintenance as the stat can trap air in the oil cooler.
• The stat must be tested to ensure it does not restrict the oil flow; see SI-912-005 to learn how to perform this test.
• Straight fittings must be used to connect the oil hose; angled fitting may cause oil restriction.
Perma-cool and MOCAL are good brands that have suitable “stats”
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What oil hose should I use?
The important point to remember when buying oil hose for the Rotax 9 series engines is that the oil hose is under “suction” from the oil tank to the oil pump. (See Oil system article)This is why it is important to have an oil hose that will not kink or collapse during high heat/high suction conditions. Choose an oil hose that is rated for “negative pressure” or “vacuum” operation and a temperature rating of at least 300oF.
• Any oil or fuel hose in the engine compartment should be fire-sleeved. See Fire-sleeve info
• Do not bend the hose below a 3 inch radius
• Do not use industrial fittings! Use “full flow” fittings that do not restrict the oil flow. See full flow fittings diagram
Aeroquip (AQP series and Startlite) and Stratoflex both make several varieties of hose that meets these requirements.
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I heard that the oil change is complicated, is this true?
No, the oil change is basically warming up the engine, drain & re-fill the oil tank, change the filter, run engine & check for leaks. See SI-912-010 “Oil change” and “Oil change for the 9 series” article for more information.

The following are maintenance ERRORS:
• Do not drain the oil cooler!
• Do not blow out the oil hoses!
• Do not remove the crankcase oil ports on the bottom of the engine
The maintenance instructions do not allow or instruct you to do these actions! Severe engine damage has been caused by these errors.
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First start up, what do I do?
This is possibly the most important time in your engines life. Have someone credible and experienced with Rotax 9 series engines assist you and double check your work! Use the First start checklist to guide you through the process.
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-Fire-Sleeve information
Fire-sleeve protects hose in case of a fire; it is not just to protect the hose from hot surfaces such as exhaust pipes.
• All fuel and oil hoses in the engine area should have proper fire-sleeve covering.
• The fire-sleeve should cover all the rubber hose and extend half way up the connector to prevent flames from getting at the rubber.
• The end of the fire-sleeve should be “dipped” to prevent wicking of oil.
See Fire-Sleeve info
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