Walbro Throttle Plate Orientation

[blackmojo]

Hey guys,

 

Just need to check on the orientation of the throttle plate on the cylinder side of my Walbro HDA 198 Carb. I had to remove the spindle to change the throttle return spring but obviously wasn't paying enough attention at the time!

I've attached a picture of the plate, there's 3 notches around the outside of it so I'm assuming there's a right and a wrong way to install it.

 

All help is appreciated! Thanks.

[bmp01]

There is a right and wrong way. ...

First easy thing is to look at the throttle shaft and the throttle plate for the shadows and clean patches where there has been exposure to /air and contact between parts respectively. Looking at that throttle plate, the hole on the shaft should have left a nice tell tale  circle on the shaft. 

Secondly, the outside 'diameter' of the plate isn't perpendicular  to the plate surface, because in the closed throttle position it's slightly off 90 degrees from the port centreline.

 

HTH