Main jet in carb will not tighten up what can I do?

[michaelrj9]

Not sure what category I should post this under so hopefully here is OK.

I have a Carter 9635sa carburetor that I was rebuilding a while ago and could not get out one of the main jets.

I ended up breaking off a tab so I could not use a screwdriver to remove it anymore.
I then tried to use easy outs but it would not remove it. It would bite but a little then slip, I tried a few different sizes and brands with no luck. It was to shallow to use before it bottomed out in the carb to get a strong bite.

To make a long story short I ended up drilling it out. I was careful as can be but the thread's got a little damaged. I did run the tap through the hole but the "new" jet will not tighten up.

I left it like that as it is on a car that does not get driven that much and did not have money to spend on a new carb. It seemed OK for what I needed it for.


I tore it back down now to rebuild it again but wanted to see if there is something that can be done to help it snug up better this time but (still keep it removable if needed later on which I don't know if it is possible). Before it snugged up a tad but now it will not at all. I tried about 5-6 turns of Teflon tape which did not help at all.

I heard to use marine Tex.
Is this the correct way to go?
If so, I have a couple newbie questions.

Should I just coat the threads with the epoxy and the hole a little, to hope it has something to grab on to or fill completely and drill and tap?


If fill and tap is the right way is it critical on the depth? When looking down in the hole it is tapered at the bottom just past the threads, does that need to be at the correct depth to seat with the main jet correctly or would it be OK to drill deeper as long as I don't touch the bottom? I don't have any machinery to help with this procedure except for an electric driil or cordless drill

How strong with the new threads be with the epoxy?

Thanks

[Ethan1]

 Welcome to CHP!

 I know the feeling. Done that on a few WCD's. What a pain in the arse they can be. Next time this happens, do not reaf on it if doesn't come out. Use some heat and a good penetration lube. If that doesn't work, clean the whole thing in a good ultrasonic cleaner. That helps me a lot. The crappy gas leaves that gunky white residue and usually causes the jets to be seized. If all else fails, get the biggest torx bit that is a little bigger than the orifice and hammer her in. Then use a ratchet and socket. Destroys the jet, but at least they make new ones.

 As for the jet not seating, what size/thread pitch tap did you use? Might have used the wrong size tap. Did you clean the threads after tapping? Look down the hole and see if everything looks correct.

 Let us know! Carter's are my next favorite carb. So, I will try helping out as much as I can.

[Ethan1]

 Re-read. You may need to drill a little deeper. Look at the other jet hole and measure the depth. Yes, do not drill too far down. Just to where it starts to taper. Also, did you use a bottoming tap? Also, I would not use Marine-Tex for the jet. You might need to take it out again.

[michaelrj9]

Welcome to CHP!

 I know the feeling. Done that on a few WCD's. What a pain in the arse they can be. Next time this happens, do not reaf on it if doesn't come out. Use some heat and a good penetration lube. If that doesn't work, clean the whole thing in a good ultrasonic cleaner. That helps me a lot. The crappy gas leaves that gunky white residue and usually causes the jets to be seized. If all else fails, get the biggest torx bit that is a little bigger than the orifice and hammer her in. Then use a ratchet and socket. Destroys the jet, but at least they make new ones.

 As for the jet not seating, what size/thread pitch tap did you use? Might have used the wrong size tap. Did you clean the threads after tapping? Look down the hole and see if everything looks correct.

 Let us know! Carter's are my next favorite carb. So, I will try helping out as much as I can.

It is a 5/16-24 tap. I am not a tap expert (so please forgive me) but it was flat on the end. The tapered ones will not work because of it being so shallow. I did use the same tap in the other main jet hole and it goes in APX 2 turns which that is about how many threads are on the jet itself.

The hole does not look clean (meaning crappy threads) as the hole is a tad to big for the tap. the tap is loose compared to the good holes.   

[Ethan1]

It is a 5/16-24 tap. I am not a tap expert (so please forgive me) but it was flat on the end. The tapered ones will not work because of it being so shallow. I did use the same tap in the other main jet hole and it goes in APX 2 turns which that is about how many threads are on the jet itself.

The hole does not look clean (meaning crappy threads) as the hole is a tad to big for the tap. the tap is loose compared to the good holes.

 That probably your problem. Crappy threads. What size drill bit did you use? Usually when it comes to drilling carburetor jet holes, you need a vertical mill and a perfectly flat surface. If it is off just by a little bit, it will not work. Simple as that. I guess you can use Marine-Tex, but I would not recommend it.

[michaelrj9]

That probably your problem. Crappy threads. What size drill bit did you use? Usually when it comes to drilling carburetor jet holes, you need a vertical mill and a perfectly flat surface. If it is off just by a little bit, it will not work. Simple as that. I guess you can use Marine-Tex, but I would not recommend it.

I just checked again and the depth seems the same as the other one but the hole is to big on the top. The jet will sit flush when dropped in, the good one sets up about 1 turn.


If I drill deeper and tap it deeper will it mess up the amount of fuel passes through or will that still be controlled by the jet.  (as long as I don't go through the bottom of the carb


This is for a car that is barley driven and if driven only 5-10 miles at a time a couple times a year. But like to move it out of the garage maybe a couple times a month so it does not have to be perfect.

How about a helicoil? The part that concerns me about that is the length of the coil can it be cut down? Or after installation and need to break off the tab inside not sure if it will come out and not stay in the hole.

[Ethan1]

I just checked again and the depth seems the same as the other one but the hole is to big on the top. The jet will sit flush when dropped in, the good one sets up about 1 turn.


If I drill deeper and tap it deeper will it mess up the amount of fuel passes through or will that still be controlled by the jet.  (as long as I don't go through the bottom of the carb


This is for a car that is barley driven and if driven only 5-10 miles at a time a couple times a year. But like to move it out of the garage maybe a couple times a month so it does not have to be perfect.

How about a helicoil? The part that concerns me about that is the length of the coil can it be cut down? Or after installation and need to break off the tab inside not sure if it will come out and not stay in the hole.

 A Helicoil would probably be the best way to go, as it sounds like the hole is off/bigger than it should be. They make Helicoils for everything. It wouldn't hurt to try.