What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Rotax Screw ID help needed

Jeff Vaughan

Well Known Member
I found the screw shown below sitting on the left carb drip tray. Sorry the photo is rotated 90 degrees. I have searched for the spot it came from but have not been able to locate its origin.
Four additional RV builders were also unable to figure out where it came from. It is most definitely a Rotax screw because the torque seal color is an exact match to the torque seal they used on the rest of the engine. I noticed the screw before I had connected the throttle cable. It is tiny and I do not know what to call it so I can not look it up in the parts list. Any one have a clue?
6jg7pk.jpg

dcvx3n.jpg

2nvueky.jpg
 
Last edited:
I just edited my post. I noticed the screw a month or so before I ran the throttle cables.

There is not another screw this size on the other carb that is visable
 
In the illustrated parts catalog carburetor diagram I would say it is part 45, 963162 THROTTLE VALVE STOP SCREW.

I don't have a carb in front of me, but from the diagram it goes into the bracket that the springs attach to to pull the carb open. From memory it isn't an actual nut, more of a threaded spring washer sort of thing.

Or I could be wrong and it's something else entirely :)
 
Has this engine ran yet? Connecting throttle cables implies it hasn?t. It looks like the screw you remove to tap into the balance tube for the MAP sensor.
 
Has this engine ran yet? Connecting throttle cables implies it hasn’t. It looks like the screw you remove to tap into the balance tube for the MAP sensor.
Do you mean the screw on top of the intake manifold that you remove, and in its place, you screw in a barb fitting for rubber hose connection to vacuum gage for balancing carbs? By memory, that looks like the screw...
 
There’s a small screw that you remove from the balance tube (the tube that connects the two intake manifolds) It has barbs on the port and is closer to the left side. That’s what it looks like from the pics. If you’ve hooked up the tube pull it off and see if the screw fits. I can’t recall another screw like the one in MAP port.
 
Last edited:
I have not run the engine yet. I will investigate tomorrow and advise.
I do not want to run the engine till I figure this out.

Thanks for your suggestions!
 
Check the hose barb on the bottom of the carb flange. There is a screw that plugs it off threaded into it. We use the barb with a jet installed to connect a primer on an Aircam aircraft.
 
I pulled the MAP hose off and threaded the mystery screw into the barb. Perfect fit and the torque seal marks lined up.

Mystery solved. Now I can start this baby up!

Thanks VAF community. What a great resource!
 
Back
Top