1630 ACE 170 - Spark Plug Gapping and Anti-Seize

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New Member
Hey Team,

Its finally time to take my ski's out of storage for the spring / summer and have 2 questions:

1) I've been doing the annual maintenance myself for a couple years with no issues, however, I have noticed 1 discrepancy between what the Sea-Doo Manual says, and what NGK says. NGK Spark plugs obviously come pre-gapped (in theory) to NGK's specs which is to 0.7mm. But the Sea-Doo manual says 0.8 - 0.9mm.

Which should be followed? NGK or Sea-doo? I was having 1 ski run intermittently rough at idle last year and wondering if this could be why.

2) The argument around applying anti-seize on the plug threads. Again, NGK says anti-seize isn't needed because of their coating, but the Sea-doo manual says to apply it. I haven't been using it for the last couple of years and have had no issues, but wondering what others have been doing.
I just put new plugs in both my 2007 GTI 155 and 2021 GTI 170 last week, hoping to get out this week. I put new plugs in every other year, and put 25 hours per year on my skis - hope to do more this year. But I check the gap of the NGK 4339 plug (DCPR8E) and find that I rarely need to adjust them. They are close enough to Seadoo spec, but the plugs are used in many different automotive applications, so the gap from NGK is a general, most common gap. So, I check, but typically don’t adjust the gap. As for anti seize, changing plugs every other year is probably not long enough for them to seize, but there is no harm in using it. I use anti seize on my plugs, because there is no harm in using it, and Sea-Doo suggests it from what I have read. Just put plugs in until they are tight, compressing the washer seal that comes on the plug, not over tight. I just tighten them until they stop turning and stop. They are always easy to remove.
I ride year-round, about 80 hours per year. I change my plugs every 50 hours. I don't gap them and I do apply anti-seize.