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Hitachi DCH-306 Carb rebuild - 1 question (w/ pics)


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Hello, I am in the process of rebuilding a Hitachi DCH-306 carb for my 78 Datsun B210. 


Everything has been going smoothly, except! While I was cleaning gunk off of the outside of one of the pieces of the carb, a little unidentified metal piece fell out. I can't find this piece listed in any of my carb blow out diagrams. The piece was not obvious/visible to me during the disassembly and it stayed put  while i was boiling the junk off the carb. Can someone tell me where I am supposed to put this piece back?


My main guess would be that it fits into the end of this pump return spring and the metal ball that sits in the bottom of the pump assembly. My carb did not appear to have the ball AT ALL during disassembly.. so I wonder if that metal part was used to replace the ball during someone else's rebuild or ... ?


Thank you for your time and insights - I am at a standstill until i figure out what I am supposed to do with this little part !

This is a project car for me, I am basically learning everything myself as I go along here..

This forum is greatly appreciated!


1st image - the piece in question

2nd image - the spring piece I would guess it goes to

3rd image - where I think it goes into the carb body - (this is the carb body segment I was cleaning when the metal piece fell out ... )

















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I can't find it either. Probably from another rebuild kit.


The important thing is putting a BB (ball bearing) in there, as it acts as a one way valve to prevent fuel being pushed back into the fuel bowl where it came from.

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Number 35 in the picture. Fits under the accelerator pump. There may be another used as a one way valve to let fuel out through the pump nozzle but prevent air being sucked back in on the up stroke of the accelerator pump.

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I don't know the 306 at all but similar carburetors are this way. The BB sits at the bottom of the well that the accelerator pump 25 sits into. With the spring, 35 above it

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