Remote needle valves - yuck  
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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> Engine Manufacturers Direct Support Forum >> Jett Engineering Support >> Remote needle valves - yuck
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Remote needle valves - yuck - 1/6/2007 2:01:21 PM   
Stripes


 

Posts: 633
Joined: 5/17/2003
From: Orchard Park, New York
Status: offline 		I would like to see the needle valves moved back to the front in a manner similar to OS and Thunder Tiger; and while I am wishing how about a provision for a needle valve extension.
       Post #: 1

RE: Remote needle valves - yuck - 1/7/2007 7:01:44 PM   
rmenke


 

Posts: 1684
Joined: 6/25/2004
From: Merced, Ca., CA, USA
Status: offline 		Stripes:
Sure agree with you. Am still getting my fingers in the Webra's, mostly running sports jett engines with remote now. You can buy the Jett remote system which is a very good quality unit and put it almost anywhere. Give one a try, may change your thoughts on remote systems.

(in reply to Stripes)
       Post #: 2

RE: Remote needle valves - yuck - 1/8/2007 2:22:04 PM   
bob27s



Posts: 4637
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		Thanks for writing.....

The Jett universal remove needle valve assembly is different than most provided as stock or add-on pieces by other manufacturers.

First, an extended needle is available. Contact Dub directly. I believe he has some that are about 3" long.

More...
The Jett remote is not prone to leaks. There are no o-ring seals. As long as the packing/tension nut is snugged down to provide proper load to keep the needle from turning (on its own - should be snug enough to the point you have to use a little bit of force to adjust the needle) there is no leak path. These needle valve assemblies sell quite well as aftermarket replacement parts for other engines - since they simply perform very well. Jett engines have been offered exclusively with remote needles since 2002, and continue to exhibit an excellent and proven track record.

More..
The Jett remote needle can be engine mounted or mounted anywhere you desire. You do NOT have to keep the needle mounted to the engine. In fact, in some cases, it is better to airframe mount the needle assembly. The needle assembly can be reconfigured to provide inlet/outlet/needle orientation that best suits your application. Also, having the needle completely away from the carb makes some engine installations easier. The carb ends up physically smaller.

I have provided a couple of photos showning remote needle installations - other than bolted to the engine backplate... as examples.

More.....
OS and Thunder Tiger are not manufactured in the USA. They have a technical 'isolation' and limit on liability. Try to get a USA laywer into buying off on 'undesigning' a saftey improvement. Also, thunder tiger never went with the 100% remote system (that I am aware of), but they did go through 2-3 variations on the angle mount design.

Some background on why some people have trouble with other types of remote needle systems:

- physical air leaks - sometimes these occured on the same needle design when carb mounted, but went un-noticed since the leak was inside of the carb.

- No physical air leak, but lower/no muffler pressure into the fuel system makes carb "suck the only fuel delivery system. At high power, that lower pressure suction causes the fuel to decavatate as goes through the needle assembly - gasses within the fuel bubble out and form larger air/gas bubbles that are visible and affect engine performance. (this is why you see this type of problem go away on other engines when you add a pump - it keeps the needle assembly under positive pressure, rather than under suction, and gasses do not emerge from the fuel in the same way).

- Needle valve body temperature gets to high. This causes the fuel to boil (for lack of a better word). Or, it makes the condition noted above happen more easily.

- General fuel system problems - fuel foam - improperly installed fuel tank. Tiny bubbles form in the fuel due to vibration of the airframe. Sometimes tiny enough not to be visible in the fuel feed line. However the small bubbles accumulate and form into larger air bubbles at the needle valve, and become must more visible leaving the NVA - cause all sorts of well documented engine run issues.

In summary.......
Jett's URNV assembly was extensively tested and compaired head-to-head with the original Jett carb mounted version before it was released to the market. There was no loss of performance in any respect.

Some of the Jett CL engines, FF engines and racing engines are offered with intake mounted needle valves. But it is unlikely that the RC sport engines will see a return to the r/c carb mounted design.

I hope this is helpful.
Bob Brassell

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_____________________________

Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host

(in reply to Stripes)
       Post #: 3

RE: Remote needle valves - yuck - 1/13/2007 2:26:11 PM   
Stripes


 

Posts: 633
Joined: 5/17/2003
From: Orchard Park, New York
Status: offline 		Bob, I always enjoy your posts. They always are very informative.

I know, You are going to tell me to move the needle valve.

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(in reply to bob27s)
       Post #: 4

RE: Remote needle valves - yuck - 1/14/2007 2:57:20 PM   
bob27s



Posts: 4637
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		Well, that would be the easiest and perhaps best way to complete that installation. But its not 100% required.

email Dub jettengr@sbcglobal.net and ask about a longer needle valve.

Bob


_____________________________

Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host

(in reply to Stripes)
       Post #: 5

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