icerinkdad

I am putting together a remote needle assembly using the small fine thread assemby that screws into the side of the OS 10 carb. What is becoming a problem is that the thread size doesnt appear to be either a standard english or metric size... any ideas? I want to add a small piece of brass or maybe aluminum tube to increase the outer diameter as I am having real problems keeping fuel line on the thing!
Bob Furr

jbirnsch

I ran into this problem with a OS MAX 19 steel fin that was missing the NVA. I bought a OS10 NVA and could not find the thread size. I found that a 6-48 gun tap was a close fit. It is a little tight and had to work the NVA in to the carb body that was repaired but it worked. I believe it may be a M4 x. 5 or possibly M4 x .35 thread pitch but I could not locate one locally. I found the 6-48 gun tap at the hardware store for $2.50.

Hope this helps.

Jason

combatpigg

My Feedback: (3)

I've used the OS.10 needle as a RNV for many years for bladder systems. The trick is to jam the tubing up into the threads,as far up as it will go. I use mostly Sullivan small silicone tubing, which was enough to keep a .36 from going hungry.

dieselbloke

[quote]ORIGINAL: jbirnsch

I ran into this problem with a OS MAX 19 steel fin that was missing the NVA. I bought a OS10 NVA and could not find the thread size. I found that a 6-48 gun tap was a close fit. It is a little tight and had to work the NVA in to the carb body that was repaired but it worked. I believe it may be a M4 x. 5 or possibly M4 x .35 thread pitch but I could not locate one locally. I found the 6-48 gun tap at the hardware store for $2.50.

Hope this helps.

Jason
[/quote

The OS 10 NVA body and a whole lot of other NVA assemblies is M4 x 0.5. This is a very common metric fine thread everywhere in the civilised world.

]

jbirnsch

dieselbloke,

A 6-48 gun tap is is pretty common in civilised countries where they are allowed to have guns

Jason

dieselbloke

Maybe that should be "where they need to have guns"

You will find that McMasters etc do sell M4 x .5 taps and dies at reasonable prices.

It's not good engineering practice to use similar but not exactl screw threads.

icerinkdad

Chuckling... I sure didnt intend to have folks sniping at each other! Thanks for all the great advice. I will probably have to order the tap since the local hardware stores here in the USA dont even carry english unit fine thread taps.
Bob

ocelot31454

Try finding an Automotive carb shop for a tap. The OS 10 & 15 use needle and o-ring so you migh get a new backing plate for the OS 15 and cut the needle assy off of the backing plate to uos as the remote adjustment. Just leave the needle on the Engine wide open.