Carb on old 5.9 mill?

[Learningnitro]

Hello have a question bout the carb. What is the big brass screw on exhaust side of carb for and what should the base setting be. Mine keeps working itself out and wanting to know if I should plumbers tape it maybe or how to stop this from happening. Looked online but can't find any think it's the old carbs anything helps guys

 

[Gazzman]

That's the mid range needle jet and yes when these K series mills get a bit old the O ring on the needle that acts as a seal goes abit hard and then shrinks in size. This makes the needle loose in the thread and will wind out with the vibration from the mill. Also a good place to get an air leak which causes tuning issues. These mid range needle are very hard to find new I have look for them myself. You could use a small amount of silicon sealer like what is used in bathrooms on the threads of the needle or just seal the end of it. I just put a bit of masking tape on the end of mine to stop them winding out, The needle is normally flush with the carb body from factory setting and there is no need to adjust it as the adjustment can be made on the low end needle on the other side of the carb.
The low end needle is a needle that moves in and out of the Mid range needle to increase or decrease the amount of fuel the carb gets, the mid range needle is just an opening that the low end needle moves in and out of. Just seal the MRN with what ever you have to hand and adjust with the LSN.

 

[Jam 1]

I just sealed up my mid range mixture needle with silicone RTV on the Axial .32 it came with and it doesn't move, of course I made sure it was flush before I just sealed the whole opening outside, still on there today...

 

[Gazzman]

I just sealed up my mid range mixture needle with silicone RTV on the Axial .32 it came with and it doesn't move, of course I made sure it was flush before I just sealed the whole opening outside, still on there today...

Yes I think the mid range needle is a waste of time having and totally not needed, like you i just seal mine up once flush. I am inclined to put abit of masking tape over mine once sealed with silicon sealer. Like Learingnitro said they seem to become very loose after very little uses, must be the heat that causes the O ring to go hard.

 

[Gazzman]

Hello have a question bout the carb. What is the big brass screw on exhaust side of carb for and what should the base setting be. Mine keeps working itself out and wanting to know if I should plumbers tape it maybe or how to stop this from happening. Looked online but can't find any think it's the old carbs anything helps guys

Forgot to say, the base setting is flush with the housing. Don't use PTF tape, use silicon bathroom sealer or any silicon sealer as it will be nitro fuel proof, others will dissolve over time.

 

[Learningnitro]

That's the mid range needle jet and yes when these K series mills get a bit old the O ring on the needle that acts as a seal goes abit hard and the shrinks in size. This makes the needle loose in the thread and will wind out with the vibration from the mill. Also a good place to get an air leak which causes tuning issues. These mid range needle are very hard to find new I have look for them myself. You could use a small amount of silicon sealer like what is used in bathrooms on the threads of the needle or just seal the end of it. I just put a bit of masking tape on the end of mine to stop them winding out, The needle is normally flush with the carb body from factory setting and there is no need to adjust it as the adjustment can be made on the low end needle on the other side of the carb.
The low end needle is a needle that moves in and out of the Mid range needle to increase or decrease the amount of fuel the carb gets, the mid range needle is just an opening that the low end needle moves in and out of. Just seal the MRN with what ever you have to hand and adjust with the LSN.

Thank you sir I thought I had read about that exact thing in here just wanted to double check and gonna probably silicone it to be done with it however I do have a thousand different size o rings so may try and find one that fits first just to see. Also how did it go changing over to the newer carb for you seen that it would work but nothing after. Also I did post pics of savage after rebuild have done more to it and am loving the flysky system all around but so far only using for the one model. Range and response are awesome and now have melted top bulkhead cover for transmission so gotta order a new one and re mesh to reduce friction and heat I think I may have fused my shaft to pin holding slipper as of first messing with it can't get the silver backplate off that site on the pin. Robinson gears are awesome and all the teeth still look great. So much power. I'll post more updated pics on the build thread soon.

 

[Gazzman]

Also how did it go changing over to the newer carb for you seen that it would work but nothing after.

Changing the carb never happened in the end. The carb I bought was for a Force F5.9 mill, was hoping it would fit on the K5.9 but the necks of the carbs where they push into the crankcase are different sizes The K series has a 15mm neck where as the F series are 14mm, so ended up just doing a strip, clean & rebuild on the K5.9 carb. The carb it self was ok just had the same issue with the mid needle vibrating loose. Like you I have hundreds of O rings but couldn't find one that would work well so just sealed it up instead.