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The 2-Stroke Garage => Turning Wrenches => Topic started by: SoCal250 on October 14, 2021, 08:31:11 PM

Title: Mikuni VM20SC needle jet
Post by: SoCal250 on October 14, 2021, 08:31:11 PM
Working on some old VM20 spigot-mount carbs and they have an unusual 2-piece 145 series needle jet, where the main part unscrews from the bottom, along with the main jet. The spray bar portion remains in the carb body and I'm not sure it really needs to come out. It's pressed-in from the top and looking through the bore I don't see any perforations in the brass that would require it to come out for cleaning. It's just a short piece with threads in the ID in the bore and a spray bar protruding up through the carb throat. So I'm thinking it doesn't need to come out.

Nothing in the factory service manual about it and the parts fiche only shows the bottom portion of the needle jet that I have removed.

Just wanted to verify I'm good to go. I thought about driving them out with a threaded-in bolt from the bottom but I think it's a unique M7 thread pitch (and probably unnecessary).
Title: Re: Mikuni VM20SC needle jet
Post by: Striker1423 on October 14, 2021, 09:05:30 PM
Similar to what's on my Evinrude outboard. Dip the carbs and clean it. But, I wouldn't worry with removing the inner tube.
Title: Re: Mikuni VM20SC needle jet
Post by: SoCal250 on October 15, 2021, 11:50:25 AM
Quote from: Striker1423 on October 14, 2021, 09:05:30 PM
Similar to what's on my Evinrude outboard. Dip the carbs and clean it. But, I wouldn't worry with removing the inner tube.
Cool thanks, that's what I was thinking. It doesn't look like there's anything in there that would require additional cleaning. The bodies have been run through the ultrasonic and blown out with compressed air, so I should be good.