Zenith stromberg metering needle removal help

[ichthos]

I know how many people have said how easy it is to rebuild these carbs, but it sure looks like I am going to need lots of help. Can someone explain how the metering needle is removed? I removed the small set screw, but it still does not come out. What else do I need to do? Thanks, Kevin

 

[swift6]

If you have one of the 'adjustment tools', use it to turn the needle out as far as you can. Since you've already removed the set screw, you push the needle out(its easier with a thin wood dowel). The needle is held in with an o-ring that is probably swollen and a star washer. You might have to give it a pretty hefty shove if it hasn't been out in a while.

 

[TR3driver]

There are some great articles at
https://www.buckeyetriumphs.org/technical/technical.htm

To remove the metering needle, you need to completely unscrew the mixture adjustment inside the guide rod. Best to start this process with the set screw in place as it keeps the needle carrier from turning in the piston. Then remove the set screw when you can keep the carrier from turning with your fingers.

Once the needle & carrier are out, insert a suitable rod into the hole (I used an unsharpened pencil) and tap the adjustment screw out through the guide rod. There's an O-ring on it that you'll probably want to replace.

 

[swift6]

Unsharpend pencil is a great suggestion for that. :thumbsup:

What number of lead do you find works best? :wink:

 

[ichthos]

Sorry to be so dense, but I just don't understand how to remove the needle. I don't know what the guide rod or mixture adjustment is. I removed the screw from the side and pounded a pencil down the center. All that happened was that the pencil broke. I don't know if this makes a difference, but the carbs are from a 69. There is no adjustment for the needle. I tried to just use plyers to pull it out. Nothing happened. I am afraid I will ruin something at this point. Can anyone give me a less technical lesson on how to remove the needle?

 

[glemon]

ichthos, I just went through this on a Zenith carb. You need to get a long allen wrench and stick it down the damper as you would to adjust the mixture (the tube you put oil in to dampen the the piston movement) I don't know the exact size, moss and other sell it as Zenith Stromberg adjusting tool.

You need to turn this counter clockwise (as you look down at it) unitil the needle is at its lowest, this takes the needle off its threads, then you loosen the setscrew in the side of the piston and the needle should come right out.

Be careful using a pliers on the needle, you do not want to scratch it it all.

 

[TR3driver]

Sorry, Kevin, I didn't realize you had the early CDSE carbs without the needle adjustment feature. On those, I believe the theory is what you've already tried : loosen the setscrew and pull the needle and carrier out.

Unfortunately, if it's stuck, there isn't any good way to apply force without damaging the needle. You could try soaking it in solvent or penetrating oil. Then when that doesn't work, try applying some heat (propane torch) and tugging on the needle with a rag wrapped around it. Don't get it too hot though, you don't want to soften the metal.

But if that doesn't work, and you have replacement needles (and carriers) on hand; then just grab the old ones with pliers or vice grips and go to it. Once the needle has pulled out of the carrier (which it probably will), you can probably work the carrier out by threading a suitable tap into it, then dropping some sort of spacer (couple of big flat washers maybe) over the tap and turning a nut down to pull the tap out with the carrier attached.

Otherwise, just leave them alone and hope they are OK

 

[Stig]

Take a paint stir stick and break it in half. Place the 2 pieces in a bench vise. Slide the needle between the 2 pieces of wood and clamp firmly. The needle will be clamped but not damaged. Then carefully rotate the piston, while pulling up. A little PB Blaster or Mouse Milk will help. I have done this 30 or 40 times and it has always worked.

 

[TR3driver]

Stig, I believe your TRs have hard-mounted needles. The TR250 and TR6 used a soft-mounted needle with a spring-loaded carrier on the piston end. Pulling hard on the needle might not damage the needle using your method, but it stands a very high change of damaging the spring/carrier. And turning the needle will only turn it inside the carrier, not where the carrier is stuck in the piston.

 

[ichthos]

Well, you are correct Randall, there is a fixed needle and there was a spring carrier (not any more). When I pulled on the needle, first the spring came out, and then the needle broke off. I drilled down the center to get the rest of the needle free. I used progressivley larger drill bits until I could pull the spring carrier out. Thanks for all of your help everyone.
Kevin