Rotax, Rotax 447, Rotax 447 parts.

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The proper spark plug for use in most of the Rotax engines is the NGK B8ES, or other brand name equivalent, (Champion spark plugs are not recommended, nor are they factory authorized for ultralight use.)

If using a spark plug with an BR in its heading, (usually used for ignition noise suppression) such as NGK BR8ES, a resistor cap should not be used. This is because of the double resistance supplied when using both a resistor plug and resistor cap. It is advisable with engines running in the inverted position to use a spark plug with an extended electrode. This aids in stopping spark plug fowling. Look for a BP in its heading (NGK BP 8ES).

When removing or installing the spark plug cap make sure that the cap is turned, in the rotation necessary to tighten the screw on cap on top of the spark plug, otherwise the improper removal of the cap results in the backing off of the screw on cap and the possible loss of spark to the engine, when the spark plug cap falls off. Also see resistor plugs vs. resistor caps!

The recommended gap on the spark plugs is .015 to .019  of an inch. These plugs are capable of running for over 20 hours trouble free on a points and condenser engine and up to 50 hours trouble free on a dual CDI ignition engine (if proper fuel and oil are used and the engine is in proper tune). They should be checked on a regular basis however, and replaced at the first sign of a miss or after severe flooding of the engine.

If using a cylinder head temp gauge, removal of the ring on the bottom of the spark plug is recommended, since the gauge sending unit replaces it. (Cylinder head temperatures should range in the 300 to 400 degree F range.)

In practice, a properly tuned engine should show a nice chocolate, or brown color on the spark plug, white indicates an engine running hot, while black indicates one running to rich. Any sign of aluminum on the spark plug indicates a problem of a very serious nature, and requires your immediate attention!
Also see "How to read your spark plugs"

A regular replacement item.  Suggested replacement every 150 hours, or at the first sign of coil failure. When installing new coils on twin cylinder engines note coils are wired #1 coil is pole 1 to ground while 15 is to points. #2 coil is wired 1 to points and 15 to ground.
When routing ground wire lay it flat against coil so wire does not bend back and forth in the wind-which could cause wire failure and loss of ground.
Also make sure bolts are reinstalled using blue Loctite, or they will come out - these holes use self tapping bolts, without Loctite they will come loose, causing loss of ground, which will result in loss of ignition, or or coil.

Rotax Cageless Bearing

Rotax Circlip   all Rotax 2 stroke

Rotax Wrist Pin   447

Rotax Pistons

447 Standard Rotax Piston with rings

1st over447 Rotax Piston with rings

447 2nd over Rotax Piston with rings

Rotax Gasket Sets