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Threaded Screw Hole Carby

Hello all,

First time poster, long time reader :)

My EJ has a bit of a rough idle and I was in the process of ensuring that everything is where it should be and is not loose and I noticed that I have a possibly threaded screw hole on my carby. The screw in question (circled in the picture) cannot be tightened. It seems to just turn of it's own free will. The screw itself has a decent thread on it, so I am assuming it's the actual hole. I was wondering if there is any way to remedy this or is it time for a carby upgrade? If so, any recommendations on type and where to purchase?

Excuse my ignorance if I don't make any sense, I am still learning. Everyone here at OldHolden has been a saviour.

Any help offered will be greatly appreciated!

Cath

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Comments

Yeah the screw is sitting up a little bit...so if you are turning it clockwise and it wont pull down tight then wind it out by hand or screwdriver as you are going to have to check if the thread is stripped in the carby.[damaged]

When you get the screw out you are going to have to check for broken threads in the hole.

If you don't own a compressor would you have a can of compressed air as you need to blow that hole out.

What I would do is check the depth with my vernier and if possible leave the washer off the screw and just pick up any remaining threads at the bottom of the hole.

btw that screw won't be making your car run rough.

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Disclaimer :- The above is purely speculation and is only posted for entertainment purposes!!!

Hiya, that is common.The older the object ,the more threaded/burred/rounded fasteners it will have.
What to do. Use a threadlocking compound such as loctite> add a drop to the screw and tighten it down .Be gentle dont use all you strength and the correct size screw driver,one that has its head size as close as possible to to the size of the screw head A mm each way is ok.Why? the bigger the screwdriver the more force can be applied and the greater the chance of threading the screw. If smaller the greater the chance of burring the slot at the top
Try recutting the thread in the hole , the carby is soft alloy so dont again use excessive force and dont get any metal cuttings inside the the carby .It will need a specialised tool. Will be best to take carby off and give it an overhaul at the same time
Use a slightly larger screw,but of the same length, and it will cut its own thread into material as you screw it down. Then unscrew it, blow grit away and put loctite on the new screw and tighten it. Tight is all the way down with no loosness and then a quarter to a third of a turn more.
Use liquid metal compound >read the instructions first

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Hi Cath.

As per car13 with the lack of torque on the screw it is unlikely it is causing your engine to run rough. Someone has overtightened it at some stage and stripped the thread. You could try a little thread tape around the screw or even a match stick in the hole, and tighten it up that way. They're only small screws so they shouldn't be leaned on too hard. No need for a new carb.

BTW, mine has a plate that runs across those two top screws. Yours seems to have a ridge across it which would make a plate impossible to fit, they must have changed them in later versions. Here is a pic FYI http://gallery.oldho...

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"It was then I knew I'd had enough, burned my credit card for fuel
Headed out to where the pavement turns to sand...."

Cheers, John

you can heli coil the thread, the size is a weird one, 3/16bsw - i couldn't get a kit locally had to get it from the uk.

the easiest way for you to fix it is a small but long bolt and a nut underneath it.

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To try and get a definitive answer...

I was thinking that was a blind hole...but I would still take the washer off the existing screw and see if there is a couple of threads still left at the bottom to pick up on.

Or failing that does a 3/16 whitworth brass round head fit through and a nut on the end work.

Just thinking out loud really now...

http://i.imgur.com/f...

Or any other ideas.

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Disclaimer :- The above is purely speculation and is only posted for entertainment purposes!!!

that this thread is stripped. all of the above are good solutions. try the washer removal. if it picks up a thread, pull it backout and drop some araldite in the hole before re fitting the screw. this will help hold it together

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Also try interchanging the screws. I found this fixed the problem.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Thank you for the feedback.

When I took the screw out, it was definitely complete, but there was a bit of material that came out of the hole when I pulled it out. The screw is not quite as deep as the bottom the hole. I didn't get a chance to do anything b tonight, but will be into it tomorrow afternoon. I'm going to give a longer screw of the same gauge a go. I've got some locktite in my menagerie which I will put to use.

I've had the car for a few years now and not sure when the carb was last overhauled. Is it worth doing? Just to know that it's done.

Will also continue the hunt for the cause of my rough idle.

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If you can remove the Washer it might give you some extra thread by allowing the screw to delve deeper.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Check that all the manifold nuts and the carb base nuts are tight. It's common for them to work loose and cause air leaks.

This might also be caused by ignition problems like faulty leads, worn out rotor button, burned points etc.

Check the idle speed isn't too low.

Pull the choke right out for a just a few seconds while the car is at cruise. The extra vacuum can clear out any blocked jets.

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T

My Shed

Holdenpaedia, they're the brakes Mate.

Found a couple of the manifold nuts near the back of the motor had worked their way loose. They have been tightened up. Also, found the ground cable to the starter motor had a really dodgey connection (frayed/broken and crusted with oil). I've replaced the connection and cleaned up the fixings. Also replaced the battery leads as they were quite old and had started to fray at the ends.

Will put it all back together tonight and see how she runs.

Thanks again!

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You can re-drill and tap the hole using the next size up, which would be 5mm. Check your tapping/drill size chart first.

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"If your car has quarter vents, a diff at the back, and was available with wind-down windows, you may talk to me.
Otherwise I am not interested. Amen."

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