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Engine basics => Engine set up tips => Topic started by: Laurent V on March 16, 2023, 08:36:44 AM
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Hello,
At OS Engine catalog there are several NVA references, do you know the physical differences between this two version :
- O.S. Engines 22311000 NEEDLE VALVE ASSEMBLY 20-40FP-S
- O.S. Engines 21711000 NEEDLE VALVE ASSEMBLY .15 FP-S
Thanks for your help
Best regards
Laurent
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Hello,
At OS Engine catalog there are several NVA references, do you know the physical differences between this two version :
- O.S. Engines 22311000 NEEDLE VALVE ASSEMBLY 20-40FP-S
- O.S. Engines 21711000 NEEDLE VALVE ASSEMBLY .15 FP-S
Thanks for your help
Best regards
Laurent
The first one, 22311000, is supposed to fit OS engines ranging from the .20 through the 40 FP series, and they will work with the LA .25 through .26 venturis also. If you have any in that part number, what color header card is on the package. If it's a black and white header card, it may be a slightly bigger diameter than the blue and white header card. In comparing the two side by side, the needle portion on the older black and white header card is longer and more sharp. The last production versions of the .20 through the .46 needles have a more blunt end with less taper. I usually take the needle, chuck it up in a drill, and spin it as fast as possible and work the needle down with a fine file. I have been trying to find the time to do through my collection of stuff and double check the different vintages of nVAs that I have that are still new in package for variations. From some troubles I have had and from what I have read of other peoples problems, I strongly suspect that when stock of the original FP-.20 through .40 NVAs ran out, they just reworked the FP-15 NVAs toi fill in the breach to get the LA series t o completion. Regardless of what you see in a catalog or on a web site, I don't think OS has any OEM needle valve assemblies in stock. The eBay seller shttrman, (Bob Brooks I think his name is) has had some new needle valve assemblies made by Enya to OS specifications. if you are looking for some. The second one is just what it says, is for the FP.15 and is probably the same one for the LA.15. I want to really compare and measure that one also and hope to do that soon. I think I hav new in package needle valve assemblies fo r all to do this.
Type at you later,
Dan McEntee
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do you know the physical differences between this two version :
NO ,
But the .15 one'll be NARROWER ; and IF its the SAME as the .10 one ,
http://sceptreflight.com/Model%20Engine%20Tests/OS%20Max%2010%20FSR.html
Likje wot this one ere is ! , ( pictured ) you can screw the needle out till it faLLS OUT ,
and it's still to lean . in a G-15 S Tigre ! LIKELY in a .35 such as a McCoy, too . . .
So , the Olde Trick of a 1.5 m.m. DRILL BIT though it, both ways , might get you in buisness .
Just thought Id bring it up. Its the little wasted spray bar
O' ring 'd needle swine ,
Fits G 15 so OS 20, 25 etc . inadequate bores for adequate fuel , om the bigger engines .
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Thank you for your answers. I have a TT GP25-ABC engine and I can only find in stock in Europe the reference OS 21711000 (blue label). Can this model be suitable, should it be adapted or it is not compatible ?
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I put the NVA through the pinch bolt hole in the crankcases of all my GP 25s and GP 40s.
The bolt is 4mm dia and one of the numerous Super Tigre NVAs fits putting the outlet hole close to the middle of the crankcase.
The OS NVA that fits the FP 20 through to the LA 46 is 3.5 mm dia.
I don't have any .15 engines but the NVA for my FP 10 is 4mm dia with the area across the venturi opening reduced in diameter.
I suggest that you look at ST replacement NVAs for you GP 26.