Stuck needle jet (main nozzle) in Hitachi Carburetor

I have a stuck needle jet in one of my Hitachi carburetors. Any words of wisdom on how to extract it without damaging the nozzle or carburetor body?

 

how's it stuck? is the jet stuck?

 

I have heard that boiling the carb in water will loosen up, and clean them. I don't think that I would submerge it completely because of the diaphragm. I boiled my rack, less the diaphragms, and it really helped get them spotless.

 

I was able to remove the jet from the float bowl side. The needle, slide/diaphram is removed. This is the (i think another name is emulsion tube) from the carb body. I really did not want to strike it with something thinking if I slip i could damage the brass threads. The other 3 either dropped out or just needed a push after removing the jet.

The carb rack is together so I do not want to submerge it in boiling water. i would probably distroy the throttle shaft seals.

 

I boiled my for about 20 minutes with no damage to the shaft seals. I just did not want to boil the diaphragms.

 

If the tops are off (no diaphragms), flip the carb rack upside down and dribble carb cleaner onto the emulsion tube from the float bowl side (now facing up). You don't need to spray it in there, thus making a mess. You just need to get the tube nice and wet. I would plug the other side with a shop towel (meaning: hold it there with my hand) to make sure it gets good and soaked, then remove the towel.

The carb cleaner won't evaporate in that tight space with no air flow. Let it work for a minute or two, then GENTLY tap on the tube from the float bowl side. Use a small socket (4mm? maybe smaller) or other drift that almost completely fills the hole so as not to damage the tube. As you say, you do NOT want to put anything INTO the tube as a drift, since that will damage the threads where the fuel jet will need to seat later. Remember, you're trying to fill the hole the tube FITS INTO, NOT the hole IN THE TUBE.

You shouldn't have to give it much force at all, and the tapping is just to "encourage" it to slide on out. Once it breaks loose, it should just fall all the way out. And you don't have to treat it like glass, either. While brass is quite soft, as long as your drift is seated well against the entire face of the bottom of the tube, you can give it a decent whack without hurting it. Use a small hammer, a good drift, and a "less is more" attitude and you'll be fine.

As a guideline, don't give it enough force to wedge your drift into the hole when the tube pops loose. What you want is for it to break loose so that it FALLS out. You should NOT be trying to DRIVE it out. If it moves a little, go back to using your fingers as soon as you can grab it.

If it doesn't come loose with some gentle tapping or only moves a little and you still can't work it loose by hand, re-apply carb cleaner and WAIT SOME MORE. The chemical does need time to work, and there may be enough gunk in there that one - or even four - times may not be enough to dissolve sufficient crud to knock it loose.

You'll get it out. Patience, time, and a small hammer will eventually knock it loose without damage. Emphasis on patience. Brass parts in carbs more often get broken when WE (meaning "I") just get frustrated and tired of dealing with it and just want the thing out. That tube is a pain to replace. Let the carb cleaner work and have something else to do while you wait.

Sorry that ended up being so long.

EDIT: One other idea. I have gotten a couple of these unstuck BY HAND by removing the jet, removing the spacer, then re-threading the jet back on partway (as far as reasonably possible, given the task) and pushing with my thumb. At the very least, you'll know just how stuck it is, and you're unlikely to damage anything as long as you are using just your fingers.

DO NOT USE THE JET AS A DRIFT. Even if you don't care about the jet itself, you're still banging on the threads of the tube if you do that, which are smaller and much more important than the face of the tube. Those threads are only meant to be strong enough to hold the needle jet (the tube itself) and the main fuel jet together. They are not meant to bear any kind of load whatsoever, so don't ask them to.

 

I wonder if this would help?
http://www.allelectronics.com/make-a-st ... CAN/1.html

 

Rhys forgot to mention in the hole for that imulsion tube not too far in is a locating pin that if you use a 4mm socket to drive the tube out may hit that pin and damage it.
My suggestion would be to use an old jet as Rhys suggests and get the tube moving down to that location pin and then work on it from there.

MN

 

Which is precisely why I said the object was to break it loose, NOT drive it out.

If it's still stuck enough to need being driven out, it needs more carb cleaner.

 

And how do you know that? You can't see them; they're trapped and if you did cause them harm you won't know it until you start having sporadic "leanness" issues or flat spots in the powerband for no apparent reason.

It is highly NOT recommended to submerge still-assembled carbs in anything, because of the possibility of doing damage to the throttle shaft seals.

If you got away with it (for now) fine. Others might not be so lucky.

 

Thank you for all your responses. I will try the carb cleaner and old jet and see if I can free it that way. I will have to look at the other carb bodies for that locating pin. I don't remember seeing it.

 

Thanks guys. Spraying it down with carb cleaner and reinstalling the main jet for something to move the emulsion tube with was enough to break it free.

 

+1
I boiled my airbox to carb boots a while back and they shrank big time.