Excessive fuel burn after 100hr inspection

I've taken Lockwood's maintenance courses and been assured that the NGKs still work just fine, as they always have... there is no "tradeoff".  NGK just doesn't want any aircraft liability, but their sparkplugs are great.

Ryan Green wrote:

Aircraft is an RV-12 so there's only 1 tank and thus no fuel selector, other than the cutoff valve which never gets touched outside of checklists making sure it's open. Carbs weren't pulled/opened as it was at its first 100-hour service, ever.

I ordered a set of the Official And Expensive Rotax Spark Plugs from Lockwood the other night as I couldn't get a straight answer after hours of searching this and other forums about the potential tradeoffs between them and the NGKs. Included in that order is a big tube of Silicone Heat Transfer Compound, and a torque wrench coming from elsewhere.

As was mentioned before, per 14 CFR Part 43, replacing the spark plugs falls under allowed Preventative Maintenance, so I'll be doing it myself. If this doesn't get resolved, there's a Rotax iRC somewhat nearby I'll be running this to (and honestly, probably taking to for its 200-hour).

The on/off valve has the same thing: a seal around the rotating shaft between the inside and air.

Closing this out:

I installed new spark plugs and used the silicone heat conduction compound sold by Lockwood, and my fuel consumption issues were immediately resolved. For those of you who come here by doing a Google search for "rotax 912 thermal compound" – this is for you

The gaps on the plugs I pulled were mostly within spec but on the wider side.