I'd prefer not to pull it out again, (let sleeping dogs lie so to speak), however unlike old mate that cut grooves and added o-rings to seal things up I just ran a tubing cutter around it a few times (where the yellow line is drawn) and it formed a grove with a raised edge on each side very similar to what it did on the aluminium scrap pictured. In fact, the groove was much shallower than the one pictured and it still was too tight and needed some swipes with 1200grit to get it to fit as well as spin it around a few times to "wear" it in. It's not the groove that's important, it's the metal being displaced by the forming process that closes up the gap. It probably only happens in 1 in 1000 engines and a new throttle assembly would be the correct solution.

The surprise to me was that when I went to empty the pump by sucking on the injector line with a syringe with the throttle open like I've done heaps of times with my DZ170, I got a syringe full of air?? That test applies a vacuum to the pump and to the sub needle circuit and,to my surprise, air was very easily coming in from somewhere else. If it's sealed right, it's also a good test to see if your sub needle is actually sealed closed.

I'm hesitant to break out the champagne just yet.



Formed groove made where yellow line is drawn.