Solved: Help With Identification of Carburetor Screw

Green Bean

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Trying to fix a rough idle issue... I removed the carburetor to tighten the studs. When I lifter up the carburetor, this screw fell onto the manifold. Now the engine runs like crap, won't idle and it makes a loud whistle. I sure would appreciate guidance on where this mystery screw goes.. For reference, I have also attached a picture of the carb from when it was installed a while back.
Thanks!

Carburator Screw.1.jpg


Carburator Screw.2.jpg


Carb.jpg
 

flx

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Jan 4, 2019
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Yes, if your screw has a hole in the center going through, it goes in the hole mentioned by Byron:
1656793861629.png


Vacuum pass through it to pull the power piston on the main circuit. I would think that without it the power piston never actuates but not sure it would cause an issue at low power situations.

It also participates to keep the main body of the carb bolted to the base. Without it I think you only have 2 bolts on the same side connecting the 2 so maybe you have an air leak.
 
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Green Bean

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Thank you Byron and Fix. I'll be pulling the carb off tomorrow and hopefully resolve the issue. I very much appreciate the sage advice.
 

Green Bean

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Thank you everyone for the valuable help. That was indeed where the screw went. It has been re-inserted. In the process of de-bugging, I encountered a couple of the carb manifold studs were stripped. I ended up using 2 M8 x 1.25 heli-coils which worked perfectly. Re-torqued the carb. Tinkered with the idle adjustment and air mixture a bit and it now idles steady at 700 rpm. This forum is tremendous.
 

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