Anyone who owns a new SDI-equipped Ski-Doo is going to need to know the specific spark plugs that are recommended for their sled. NGK BR9ECS, you say? That’s a start; there are different versions of this spark plug, making matters confusing. We’re not talking about the traditional screw-on aluminum terminals and solid terminals, we’re talking different gaps.
The newer BR9ECS spark plugs will have an additional number on them, a â€œ5â€ or an â€œ8â€ for example, right underneath the â€œBR9ECSâ€ on the porcelain section of the plug. This designation indicates the preset plug gap so you use the proper spark plug in the proper engine. Plugs with a â€œ5â€ indicate the gap is 0.5mm (about 0.20â€ for those who are non-metric) and plugs with an â€œ8â€ have a gap of 0.8mm (about 0.30â€). Most all of the newer lean-burn SDI engines will call for the larger gap â€œ8â€ version. The PowerTEK 800s are less picky in this regard, they can run either without much of any issues. Take a look at the (black and white) specification decal under the hood that lists the EPA data and it should indicate the appropriate spark plug for that particular engine. Ideally, this is the plug that should be used.
According to NGK, one should NOT attempt to adjust the gap on these style plugs, but those who have done so know it can be done with caution. Some dealers are buying their NGK BR9ECS plugs from sources other than Ski-Doo, so they may not be paying attention to the specific gap for each model. It is more critical with the SDI engines than any other to use the right plug.
Why not just an NGK BR9ES? Properly gapped, it should work just fine if you’re in a pinch (and don’t have an ECS). One of the benefits of the ECS design is at wide open throttle (WOT) the shorter electrode of the ECS doesn’t get as hot as the standard ES, helping to avoid detonation on the lean-burn engines.