Parts on diaphragm assembly linkage

[mdryamaha]

I've been rebuilding my carburetors and can't seem to figure out the parts on the linkage of the diaphragm assembly. There is one small plastic washer sandwiched by two rubber o-rings. In the configuration they were in when I removed the carb they don't appear to do anything but go along for the ride.
They can't slide closer to the diaphragm as a small metal tab prevents it. See attached pictures, any ideas what these are?

This is a 2006 Yamaha F40TLR.

[boscoe99]

Why are the carburetors being rebuilt if I may ask?

Neither the service manual or the parts catalog show those parts on the dashpot link. Perhaps the previous owner installed them for some unknown reason.

[mdryamaha]

Parts on diaphragm assembly linkage

Carbs are being re-built (cleaned) as they were heavily gummed from sitting for several years.
My feeling is that these three components serve some minor purpose. Why would the linkage arm be stamped with a detent which prevents the washer from sliding down? Although the use of washers, either cushioning or sealing, on the middle of the linkage makes no sense.
Lastly, I can't find these parts anywhere else on the carburetor or intake, so it rules out spares just slid on the linkage for access later.
Hoping someone has seen these before.

[boscoe99]

Paging our Portuguese friend Mr. Almetelo. He has an F40. Maybe he can take a look at his dashpot and see if what is installed on yours is installed on his.

Maybe it is part of the dashpot assembly and the details parts are not sold separately.

[rodbolt17]

if Boscoe can reformat the pic I could open it on my antique machine.

then I can tell you what your looking at.

[99yam40]

[rodbolt17]

I would like to give a real reason those parts are on that shaft.
however they do nothing that I ever saw.

[robert graham]

Maybe the owner put that neat little item on the shaft so he could observe the movement/position of the diaphragm shaft?....

[99yam40]

Robert, that makes more sense than any reason I could come up with

[almetelo]

My F40 also have that washer and o-rings.

What for!? IDK but in fact I made my self that question about one month ago and I can't see a reason for that thing be there.

Found that when rebuild my carbs with the Boscoe mod but haven´t test it yet.
Than I have something else to try

[99yam40]

Very interesting,so it is not the only one like that.

apparently it was not done by someone for some odd reason if more that one has them

[jonny5000g]

Quest about diaphragm

What's the purpose of this diaphragm also btw? I just rebuilt my yami 08' f40 3 carb system and am seeing this seems only to dampen the linkage coming back?

[rodbolt17]

it is a dashpot.
it helps prevent stalling at rapid throttle close.