1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

[Cap'n Chaos]

I have a service manual and a parts manual I have rebuilt carbs before but have not yet encountered this problem.

Both service and parts manuals show part 35 (needle valve bearing) then part 42 (needle valve retainer).... then then slow speed needle valve.

However when I try to assemble these parts in this order I cannot get them in far enough to where I can thread the slow speed needle valve in.

I am afraid to apply force...for fear of damaging something. The (red plastic) needle valve retainer will not fit over the threaded shaft and the bearing will not go down into the recess??

Can someone with greater experience please let me know if this just a really tight fit, am I not applying enough force... or am I doing something very, very wrong.

 

[Cap'n Chaos]

Re: 1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

Re: 1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

Oh boy... I think I just figured it out. I don't think this carb is for a 1972 Evinrude 18HP.
The number on the carb is 315082-D2. The number on the bowl is: 313355.

The correct part number for 1972 18HP is: 384529

Can someone help me identify what year/ HP carb this is please? Is this a Johnson 20HP carb?!

 

[F_R]

Re: 1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

Re: 1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

Don't go by those casting numbers on the parts, they are next to meaningless. I don't know, but I suspect you haven't removed the old bearing from the carb body. That would mean that you are trying to stack two of them in there.

Assuming it is removed, first insert the new bearing in the body, pushing it all the way in with a small rod or punch or something. Then thread the retainer on the needle till just a thread or so comes through. Place the needle and retainer in the keyhole and thread it on into the body till lightly seated then back it out 1 1/2 turns.

If you don't have two bearings in there, it should go as intended.

BTW, the red retainer does not "fit over the threaded shaft". The needle has to cut it's own thread in the retainer as you screw it through. It will be a tight go, as that is the purpose of it---to keep the needle from spinning from vibration.

 

[Cap'n Chaos]

Re: 1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

Re: 1972 18HP carb rebuild : needle valve bearing & retainer do not fit correctly?

I destroyed the new bearing trying to get it out (dental picks really came in handy)...only to discover there was not a second bearing in there.

The good news is that because I am so absent minded (this worked in my favor this time) I had bought another bearing and retainer earlier in the year... and I found had an extra float, carb gasket, needle and seat... and a few other parts too.

Anyhow I'm good to go now. You're not kidding about a "tight fit"..jeesh!

Thank you FR, once again!

*I also discovered that a 1972 20HP Johnson carb uses the same gaskets, needle & seat, needle bearing and retainer so either way I'm covered.*