Since the introduction of the E-TEC direct injection technology in 2009, riders have pretty much become accustomed to never having to worry about spark plug issues. For the most part, at least, After several thousands of miles one does have to be aware that the spark plug firing electrode does wear away after time and the spark plugs will eventually need to be replaced. This will usually manifest itself in the form of erratic operating or misfiring. Generally this can start to occur anytime after like 3,000 miles. The other day we saw a 2009 E-TEC 600 with 7,200 miles that started to run erratically, and sure enough, it had the original plugs in there and the center electrodes were quite worn, thus the gap was really wide. When an E-TEC doesn’t run right it’s almost always the spark plugs (worn) or the fuel filter (obstruction) from what we’ve seen.
Ski-Doo suggests the plugs on an E-TEC should be replaced every 3 years or 6,000 miles whichever comes first, and from what we’ve seen this seems to be pretty accurate.
Also worthy of mention is how some fuel stabilizers tend to lead foul the E-TEC spark plugs. Hate to mention names, but quite often when a popular red fuel stabilizer is used in the spring we will see fouled plugs the next fall. Granted this is probably the most used fuel stabilizer out there, but it seems to be the one that causes the most fouled plugs in an E-TEC. Use of a higher quality OEM fuel stabilizer sure seems to prevent this from occurring. Something like the XPS Carbon Free or Yamaha Fuel Med RX are the ones we like to use.
But sometimes a brand new sled will not operate correctly due to the spark plugs. In this case it is from the indexing, or positioning of the ground electrode. Ski-Doo states right in their service manual that “using an incorrectly indexed spark plug will result in poor idle and increased emissions.”
We’ve all become spoiled in how well an E-TEC engine typically performs, but this year our 2020 Summit Expert would not idle smoothly when it was cold. We would usually have to start it about 3 times before it would stay running.
Knowing this, we decided we had better check the indexing of the spark plugs. When the spark plug is installed, the open end of the ground electrode should be facing the injection spray, or at least be within 90 degrees of it. It should NOT be facing away from the injector. This ensures the ground electrode does not deviate the injection spray and ensures proper ignition – especially at idle.
When we went to check the indexing, we immediately noticed how the ground electrodes were not pointed to where they were supposed to be. Curiously, the plugs were barely torqued into the head. We then properly torqued them and they lined up (indexed) right where they were supposed to be.
Sure enough, the sled now idled properly. So the question would be why the plugs were not torqued properly, as this was the root cause of why they were not indexed correctly and why the engine did not idle properly. Point is, if an E-TEC does not idle properly, even when new, check the indexing. The open end of the ground strap should be pointed towards the injector, plus or minus 90 degrees. It should NOT be pointed away from the injector. Pretty simple. If the plug is torqued correctly it should line up in this manner as the threads on the OEM spark plug and cylinder head are designed such to have this occur for optimum engine operation and efficiency. This is why we will always install a new set of OEM plugs into an E-TEC anytime the plugs are removed. The new ones always line up. If you pull the plugs then the crush washer has been, well, crushed, and then the plugs don’t line up the same if you put them back in. Been doing it this way since 2009 without fail.
To sum this up, if your E-TEC has over 5,000 miles on it or it is more than 3 years old we’d suggest installing a new set of plugs. It’s kind of a pain doing it out on the trail or mountain. Anytime a Ski-Doo shop sees the plugs have been marked with a sharpie they start there for any kind of running quality issues. That, and the fuel filter. Statistically these two have been shown to cure a large number of E-TEC running quality issues.