Spitfire Spitfire Z-S carb rebuild trouble

[skucera]

I'm rebuilding my Zenith-Stromberg CD150 carb this weekend. My carb rebuild was going along very nicely when I found that I couldn't pull the metering needle out of the piston. I tried to screw the adjustment screw out, but the hex hole stripped when I tried to turn it. (I think a little water got in under the damper oil and rusted things solid. Grrr....) To add insult to injury, some previous owner or sloppy mechanic pressed the metering needle too far into the piston, well inside the face of the piston, which explains why my car ran rich even with the needle set to be fully lean.

So, I figured I would just have to buy a new B1DL needle, adjusting screw, and piston, wait a few days for parts delivery, and then finish the job. Well, pistons are no longer available, it seems. Metering needles and adjusting screws are available everywhere, and they're not too spendy either.

So, I have to figure out a way to get this metering needle and adjusting screw out of this piston. Does anyone have any ideas?

Does anyone want to sell an old Spitfire carb for parts? I don't have the money to go buy a rebuilt carb, or go buy a new Weber. (I bought a Weber clone 20 years ago, and it was great, but those Japanese Weber clones are now more expensive than the Italian originals, and I can't afford either now that I have kids.)

Any help at all would really be appreciated.

Scott

 

[TR3driver]

Never had occasion to try it (thank goodness!), but if you remove the retaining screw on the side and find a way to grab the needle carrier (brass sleeve in the center of the piston), you should be able to unscrew it from the adjusting screw. The adjusting screw moves the carrier to make the adjustment, so I'm guessing the carrier being jammed too high has something to do with the screw stripping.

I would probably start by grabbing the needle with vise grips or similar and pulling it out (which of course will break part of it off inside the carrier). Then either use an EZ-out to turn the carrier, or drill into it with a left handed drill bit.

 

[eejay56]

Hey Scott,
I've got one I'd be willing to let go of.

 

[skucera]

Randall, that is a great section drawing. I thought that the adjuster turned back out, up the guide rod tube. I also thought that the metering needle simply pressed in and pulled out once the retaining screw is removed. I got my screw out, but the metering needle just won't pull out.

Eric, I'll take you up on that. I think I've got your contact info on my old computer, so if I can get to that info, I'll send you an e-mail directly.

Thanks,
Scott

 

[eschneider]

I stumbled onto this thread, having a similar problem.

For the sake of posterity, I'll add that, with the screw in the side of the piston removed (holding the needle assembly), the whole needle assembly, screw adjuster, and retaining star washer can be gently tapped out from the bottom end (needle end) through the top.

This is helpful when the needle assembly won't pull out, the needle won't adjust
when trying to set the mixture, or if you're trying to replace the o-ring that keeps the dashpot oil from leaking out.

I used a deep thin wall socket that fit over the needle, but skinny enough to push the assembly through the piston.