Re: 1976/77 OMC 9.9 & 15 carb needle valve bearing

[Don]

Well, it is important to realize that this plastic "bearing" is actually a seal that keeps outside air from entering into the low speed mixing chamber through the threads on the needle valve. This piece replaces the conventional fiber packing washers and nut used on most OMC carbs, this plastic cup/seal design was introduced with the carbs used on the 1968 55hp.
I would hesitate to use the screw method you described even though I’m sure it works if done carefully with the right screw. Mumbles’ metal hook design seems a little safer. I can see how the screw threads might lock into the bearing/seal easier than the hook method, but the threads might just go through the plastic and gouge/lock into the carb body as well. I think you installation method is a great one though, the bearing/seal can not be deformed during installation if installed with the needle valve. I don’t know if this installation method will seat the bearing/seal completely, but I guess it will just pull back out with the needle if it was not seated completely.
What confuses me is that some carb break downs don’t show the plastic bearing/seal, how can the needle valve be sealed without it? Perhaps this is just an omission in the diagrams…
http://www.marineengine.com/parts/johns … B+Manifold