Rubber plugs on each side of air chamber on 1955 Johnson CD-12 Purpose?”

[JACQUES]

mostly front ones  part #77 .   I posted  for info  only for side and rear bumpers

Joining AOMCI has priviledges 🙂

[seakaye12]

If the original poster was referring to this valve assembly…..they control fuel pressure and the associated pulses.  When they are broken like this one is….your pressure tank will not develop pressure properly.

[DickS]

Sorry for creating such confusion on my end.  Seems that the rubber plug are actually plastic probably made in China and not part of the Johnson motor other than a former owner inserting into the air chamber to keep out dirt dobbers while the motor was in storage.

 

 

[Don]

OK, I see now, and agree with you.  Needless to say, those plugs are not part of the original engine and do not belong there.  Like you say, someone probably added them in an effort to keep critters out.  I would remove them and leave them out to avoid confusion.

[DickS]

I am sorry to have begun an inaccurate post that now I know was a misconception on my part.  I reexamined the plug which are not rubber but plastic that were probably made in China for a purpose that I do not know.  I am guessing that a prior owner of the CD-12 Johnson simply put the plugs into the air chamber holes to preclude “dirtdobbers” from building mud nests from Georgia red clay.  But some valued information surfaced in the confusion that I had wrought in the information on rubber bumpers inside the cowl made from tire stems.  I only have one star bumper remaining on my motor.

I am amazed by the knowledge of the folks on this forum and by the engineers who designed and built these antique motors.

Too bad there is no AOMCI chapter in Georgia.

[Don]

Replace the missing bumper to avoid damaging the hood/block.   Don’t sweat the confusion, it is tough to describe issues with the written word.  But, in this case, you were more than willing to follow through with more pictures, clarifying the issue quickly.   Thank you!

[Author]

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