Carb needle 390077

Fuel tanks, systems and parts
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ChampChump
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Carb needle 390077

Post by ChampChump » Sun Sep 03, 2017 17:15

I have searched the forum but things change over time so I'm going to start afresh. I'm trying to find a neoprene needle for the carb. I've read the various articles on the subject and as I have the round seat and use only Avgas, I think this would be the better option than the Delrin. It would be a straight replacement. Spruce offers the Delrin at an eye-watering price. Unless I hit really lucky, I'm going to have to bring something across the pond to the UK, so I'm open to suggestions, if anyone of the wonderful gurus here has any words of wisdom.

Thank you.

nic
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hangerash
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Re: Carb needle 390077

Post by hangerash » Mon Sep 04, 2017 06:00

I am getting old and the memory fades back and forth, but I thought the neopreme needle had been abandonded and were no longer produced.
The delrin needle was its replacement and needed to be lapped correctly to get it to seal, which most people failed to do resulting in a leaking carb.
Richard

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ChampChump
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Re: Carb needle 390077

Post by ChampChump » Mon Sep 04, 2017 06:18

Yes, that's what I've read in several places (so it must be true!). I think I found an old Spruce webpage that suggested they could still supply neoprene needles, if they really, really had to and with boxfuls of warnings, but when I looked again, the page had no such small print anymore.

I think we'll have to battle with the Delrin.

Many thanks.
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hangerash
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Re: Carb needle 390077

Post by hangerash » Mon Sep 04, 2017 06:25

I found this

It is necessary, if you want a leak-free installation, that the needle and seat are lapped to be leak free. See
the article on Stromberg needles and tips for that guidance. Although the Neoprene-tipped needle did not
need lapping, their use has been superceded by the stainless steel or the Delrin needles because of the
sensitivity of some of the Neoprene needles to the new fuels or additives.

Here is the article

http://occonline.occ.cccd.edu/online/rf ... 0Tools.pdf

I too sought the neopreme needle a while back and was frustrated not being able to locate any. The different formualtions in fuel seems to have been the cause of its demise. It was only attractive becasue it eliminated the lapping process required with the use of steel or delrin needles.
Richard

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ChampChump
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Re: Carb needle 390077

Post by ChampChump » Mon Sep 04, 2017 06:34

Yes, thank you, I found that, plus others similar and it does seem that the lapping is unavoidable. We've bitten the bullet and spent the money (well, my lovely partner has) and await the fun to come! I can understand that issues over fuel have caused some back-covering but it's a shame the neoprene option isn't, anymore.

I'll report back.
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Paul Agaliotis
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Re: Carb needle 390077

Post by Paul Agaliotis » Wed Sep 06, 2017 14:48

Remember to add the 4 gram weight to offset the light weight Delrin needle. Univair has it online, ACSB-84 Rev.1
Paul
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ChampChump
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Re: Carb needle 390077

Post by ChampChump » Thu Sep 07, 2017 16:50

Thanks Paul. Sorry about the delay: the notification went to my spam folder.
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Re: Carb needle 390077

Post by Paul Agaliotis » Fri Sep 08, 2017 09:39

I guess you are what you eat. Glad to help.
Paul
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