12/28/22:  NOT AVAILABLE

We are hoping for availability again in 2023.  There has been an identified problem with the coils needed for our production.  We are attempting to sort this out with a coil manufacture, however nothing is happening quickly.

We will post an update when we know more.  Sorry for the inconvenience.

(prototype CDI pictured after testing)


We converted the design over to a Single coil because the small coils available were extremely poor quality.  We were finding nearly 50% of them were shorted in the original sealed package.  As the price went up to nearly $40/coil, it was getting costly scrapping these as the supplier would not warranty electrical items.

The solution was to redesign the CDI and integrate a more commonly available single-coil.  The quality of the single coil is much better, and available from many sources.  It’s also possible for any user to replace (01-143-120 type coil) from any supplier if it ever fails.

We found the new PolarFireplug CDI has significant spark energy over the initial small coils of the previous design, which results in improved performance and reliability!





Out of stock


Contact us by E-mail (e-mail for quickest reply) or by Phone: (810) 765-0820  with any questions.

HewTech Electronics is offering A POLARFIRE Replacement FIREPLUG CDI for the 73~78 Ski-Doo & Moto-Ski’s ignitions.

The CDI redesign using the single-coil was the result of issues found on 77/78 models.  We’ve determined the cause and changed the CDI design to cover all PolarFire years from 73-78 models.  We also took the opportunity to integrate a single-coil design which increased the quality as well as the spark energy output!

NOTE:  This revised CDI design actually will advance about 4*-5* degrees initially, then retards to match OEM marks above 5000 RPM.  This additional timing advance and additional spark energy will add some lower RPM performance that wasn’t there with the OEM CDI.

The Single-Coil model includes 2 spark plug wires (plug wires can go to either cylinder).
CDI mounts in original factory location using original factory connector.
No splicing, alternate mounting or re-wiring necessary
Includes a separate Kill-Switch wire (PURPLE) for common 2-wire tether switch connection (ground the wire through tether or kill-sw to stop spark).

NOTE:  Suggest using non-resistor B8ES-B9ES spark plugs for most spark energy transfer to the plugs.  However some Digital tach’s may require the use of a BR-resistor type to eliminate erratic display operation


  • 1973~1975 TNT-F/A & 75 Everest
  • 1975 RV245
  • 1976 RV250 & RV340 (RV345)
  • 1977 RV340
  • 1978 RV/Sonic models that use PolarFire CDI


Uses original Factory 3-wire AND/OR any standard 2-wire kill-switch!


Verify that the chassis to engine (bonding) wire is connected & in good condition. Without this wire connection, the FIREPLUG CDI may not spark or operate correctly.

NOTE: The stock CDI may operate without this bonding wire, since it uses the aluminum case as a common ground. The FIREPLUG CDI case is isolated and no current passes through it, therefore the wire to connect the Chassis to Engine is necessary.

The Brown wire from the connector grounds to the engine crankcase internally at the stator plate. This wire often times breaks or corrodes over time. Verify your brown-wire does connect to engine ground coming from your engine, through the harness to the CDI.

Disconnect kill-switch harness, often times the kill switch & key-switch fail & short out the CDI box.

Verify Stator & Trigger resistance:

315-335 ohm Stator (RED to Brown)
55~60-ohm triggers (striped wires).

Additional information

Weight 2 lbs