How to avoid breaking fuel screw tips when setting fuel screws to 1 turn out?

[Samxboy]

Whilst the answer I guess is obvious....be extraordinarily careful. Seriously is there a trick to employ to avoid breaking these needle tips off in the carb bodies. Seems like it's nearly impossible to bottom down the screws so you can then unwind the required 1 rotation without breaking them. How do you guys set the screws?

[bwringer]

Just... be gentle?

And make sure they're not bent, and make sure the threads are clean, clean, clean.

I run them in before assembling the rack, and without the spring and o-ring, to make sure the tip lines up perfectly with the tiny hole and that the threads are clean. I suppose this will also help educate your fingers (two fingers, never more) as to the correct feel, and the acceptable amount of force.

The threads and o-ring get a drop of motor oil upon assembly.

[unfocused]

I take an old one, remove the tip and screw it in to clean the threads... after a couple broken tips and junk carbs, it's obvious why I do this

[Nessism]

I take an old one, remove the tip and screw it in to clean the threads... after a couple broken tips and junk carbs, it's obvious why I do this

This is a good idea. I have a tap, but I don't like using it because it removes too much material. An old screw is a better idea.

[unfocused]

This is a good idea. I have a tap, but I don't like using it because it removes too much material. An old screw is a better idea.

A thread chaser is used for cleaning threads, a tap is used for 'making threads'

I learned this the hard way.

[Nessism]

A thread chaser is used for cleaning threads, a tap is used for 'making threads'

I learned this the hard way.

Yes, of course. If you find a chaser in the proper thread size for these screws, please provide a link...

[unfocused]

Yes, of course. If you find a chaser in the proper thread size for these screws, please provide a link...

I know, right.

I didn't have enough characters so here is more and a

[KEITH KRAUSE]

Seems like it's nearly impossible to bottom down the screws so you can then unwind the required 1 rotation without breaking them.

All the above advice is helpful. I'm not sure what you mean by "the required 1 rotation". Depending on intake mods, once fine-tuned, the pilot fuel screws are commonly at 1/2 to 2 turns out from lightly seated and the best position often varies from cylinder to cylinder because of small differences between cylinders.

[93Bandit]

Use a tiny screw driver and turn it with 2 fingers only, no wrist motion. When it stops turning, stop.

Pretent you're a posh Brit drinking from a baby doll tea cup that's too small for your fingers, so you pinch it between pointer and thumb with the remaining fingers pointed out. That's the best description I can come up with.

[Cha5]

Use a tiny screw driver and turn it with 2 fingers only, no wrist motion. When it stops turning, stop.

Pretent you're a posh Brit drinking from a baby doll tea cup that's too small for your fingers, so you pinch it between pointer and thumb with the remaining fingers pointed out. That's the best description I can come up with.

*THIS*

You have to be as delicate as that tip is.

If it helps, this is what it looks like inside.

Centurion 1.jpg

[Nessism]

I just finished rebuilding a set of VM26's for a customer. All the threads were tight in this rack of carbs, so I took a previously broken tip fuel screw, and ran it down in and out a couple of times, though each carb. In the end, when installing the proper fuel screws, with the sharp tip, they screwed in quite nicely. Special thanks to unfocused for this suggestion!