Jett 50
06-22-2002, 02:40 PM
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Jett 50
I have a Jett .50 sized engine and it seems that I am always leaking fuel around the Needle Valve Packing Nut. When I tighten this nut down it always strips out the plastic piece inside. How tight should this nut be? How can I stop the leaking?
I thought that a remote needle valve assembly might help, so I ordered one, but did not receive the new nut to close off the old needle valve. Can you assist with that as well?
Thanks
David
I thought that a remote needle valve assembly might help, so I ordered one, but did not receive the new nut to close off the old needle valve. Can you assist with that as well?
Thanks
David
06-22-2002, 05:24 PM
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Jett 50
Hi David... Thanks for writing.
I am a bit confused when you say "plastic piece". The only plastic part on the carb may be the barrel stop screw. These were plastic parts on a few of the earlier engines. On newer engines, these parts are brass. The purpose of these soft screws is to prevent damage to the carb barrel. I am not sure if this is the part you are refering to. The only other no-metalic part on the carb is the crankcase mating o-ring and the idle needle o-ring.
http://www.jettengineering.com/parts/partsdwg.html
The nut holding the needle valve tension, should only be tight enough to hold the needle setting firmly. Any tighter and you would not be able to adjust the needle.
The needle/"packing nut" area, should not leak at all. There are no rubber or plastic seals. For fuel to get out of there, it has to get past the needle valve threads, which is nearly impossible to do. If it is indeed leaking from the needle area, something is wrong, and you should contact Dub [email protected] to arrange for repair.
The remote needle valve upgrade kit comes with a 3-56 screw (I'm pretty sure that is the screw size) that is screwed in place where the needle valve use to be. There is no nut or cover. You may leave the packing nut in place, just snug it down a bit more than finger tight.
As I mentioned, if you see fuel coming from the needle area, something is likely broken. Call 713-680-8113 or email Dub for his recommendation on returing the engine for service, or whether it is easier for him to send a replacement part if needed.
I hope this is helpful
Bob
I am a bit confused when you say "plastic piece". The only plastic part on the carb may be the barrel stop screw. These were plastic parts on a few of the earlier engines. On newer engines, these parts are brass. The purpose of these soft screws is to prevent damage to the carb barrel. I am not sure if this is the part you are refering to. The only other no-metalic part on the carb is the crankcase mating o-ring and the idle needle o-ring.
http://www.jettengineering.com/parts/partsdwg.html
The nut holding the needle valve tension, should only be tight enough to hold the needle setting firmly. Any tighter and you would not be able to adjust the needle.
The needle/"packing nut" area, should not leak at all. There are no rubber or plastic seals. For fuel to get out of there, it has to get past the needle valve threads, which is nearly impossible to do. If it is indeed leaking from the needle area, something is wrong, and you should contact Dub [email protected] to arrange for repair.
The remote needle valve upgrade kit comes with a 3-56 screw (I'm pretty sure that is the screw size) that is screwed in place where the needle valve use to be. There is no nut or cover. You may leave the packing nut in place, just snug it down a bit more than finger tight.
As I mentioned, if you see fuel coming from the needle area, something is likely broken. Call 713-680-8113 or email Dub for his recommendation on returing the engine for service, or whether it is easier for him to send a replacement part if needed.
I hope this is helpful
Bob
06-23-2002, 06:26 PM
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After some review and though, there are two places that might cause the "leak".
Jett engines have an aggressive front bearing lubrication setup. Often you will notice small amounts of fuel coming from the front bearing, and this is normal. The fuel coming from the front bearing sometimes slings up on the carb, the first place it can catch. It can look like this fuel is leaking from the carb. This is likely where the fuel you notice comes from.
In some cases, the fuel/pressure fitting right next to the needle an be loose and leaking. This can be removed and by adding a little blue or red lock tite, then gently re-installating it. These parts are made of brass, and tightening will break it off. That is why they are not installed really tight from the shop.
I hope this is helpful.
Jett engines have an aggressive front bearing lubrication setup. Often you will notice small amounts of fuel coming from the front bearing, and this is normal. The fuel coming from the front bearing sometimes slings up on the carb, the first place it can catch. It can look like this fuel is leaking from the carb. This is likely where the fuel you notice comes from.
In some cases, the fuel/pressure fitting right next to the needle an be loose and leaking. This can be removed and by adding a little blue or red lock tite, then gently re-installating it. These parts are made of brass, and tightening will break it off. That is why they are not installed really tight from the shop.
I hope this is helpful.
