is my low speed needle broken? evolution 46
 

i have an evolution 46 that i'm trying to adjust the low speed needle on but i think it may be broken. i never touched it before so i dont know how its supposed to work and then i nosed in the plane and now i'm using the engine on the rebuild and fear it may be broken. sorry for the low picture quality as i'm using a camera phone. the blue collar with the screw in the middle to my understanding is the low speed needle. it has a set screw on the rim which holds it onto the shaft, then it also has a little shaft that comes up and sits between the two limiters on the motor. the problem is that i'm guessing that shaft that comes up isnt supposed to move unless the screw is loose but the screwis fully tightened and the shaft moves freely with no resistance between the 2 limiters. is this right? or should the blue collar not move once the screw is tightened? thanks for any help, if you need a better description just let me know.


http://i4.photobucket.com/albums/y11...c/IMG00152.jpg

RE: is my low speed needle broken? evolution 46
 

There is nothing wrong with it. It is supposed to move. That is how you set it without using tools. I took the blue collar off all mine & set them with a screwdriver as it will move in flight on some setups.

RE: is my low speed needle broken? evolution 46
 

yea i definately think it'll move, i'll look into taking off the collar too.

RE: is my low speed needle broken? evolution 46
 

that is the way it is supposed to be, but i never can get mine set properly, the engine runs perfect at full throttle, it also runs perfect at idle, but it will not go from idle to full throttle in less than 3-10 seconds unless i am at full throttle, go rapidly to idle and then rapidly back up to full throttle! if i let it sit at idle for more than 3-5 seconds it has a hard time getting back to full throttle, it acts like it is flooding itself at idle i have backed off all the way between the two stops on the low speed, meaning my shaft on the low speed idle is against the front stop.

RE: is my low speed needle broken? evolution 46
 

Your low end is too rich.

You'll have to loosen the grub screw ( the recessed screw that sticks into the SIDE of the circular blue ring ) and then tighten the inner screw about 1/8 turn PAST where the blue limiter lets it travel now. Don't adjust it more than this.

Once done retighten the grub screw.

You may then have to adjust the high end a few clicks as well.

RE: is my low speed needle broken? evolution 46
 

thanks opjose, i was actually pretty sure that this was what i needed to do, just procrastinating! thanks

RE: is my low speed needle broken? evolution 46
 

You can probably safely remove the limiters on the Evolution engines without fear of damage as long as you have someone show you how to properly tune the engine. I was about ready to pitch my Evolution in the trash because I could never get it to transition smoothly, but then I removed the limiters and it made all the difference in the world, all I needed in my adjustments was just a fraction of a turn more beyond what the factory limiters would allow, now she runs great and I love it:D

RE: is my low speed needle broken? evolution 46
 

i adjusted the the low speed now and it transitions smoothly but still spits some fuel out of the muffler. i guess it needs to be leaned more. i also do the pinch test and it runs for a good 10 seconds before shutting down at idle which is a lot higher than the 3-5 seconds i heard its supposed to be. could it be because the evo 46 has a remote high speed needle, so the fuel runs from the fuel line to the high speed needle to another line then the carb? should i pinch the line from the tank or the line between the high speed and the carb? i've been pinching the line coming from the tank to the high speed. thanks for the info guys, its greatly appreciated, lots of new stuff to learn going from electrics to glow!

RE: is my low speed needle broken? evolution 46
 

The pinch test is a momentary thing. You go to full throttle, then QUICKLY pinch the fuel to the carb and the RPM should slightly increase. If it does not, it is not right. If it dies, it's to lean. If it takes several seconds to do that, then it's very rich.. and will spit oil/fuel.

As for the low end, well, it becomes trial and error. This is a transition thing and adjustments on that low end screw are very small, likle on the order of 1/8 of a turn at a time.. very small. Make the adjustment, then run the throttle up to full. It should immediately go to full with out hesitation. If it's to rich, it will caugh and sputter as it tries to go up, all this is the burning of the excess fuel that has accumulated.

And, if it sets for a few minutes at idle, it may/will load up but this is not the transition issue. This is fairly normal and why you should run the engine up to full throttle for at least 10 seconds before taking off. This is hard to adjust properly.. getting both the low end and the high end set properly. It takes some time and some fiddling with it to get it right. Once it's right, though, all you should have to do is adjust the high end for day to day changes in the atmosphere/weather.

The note of the engine noise should increase slightly then quickly drop back as you pinch the tubing. As I said, this should be a very quick action... the pinch and release.. less than a second for sure..like a quarter of a second ;)

CGr.

RE: is my low speed needle broken? evolution 46
 

yes, its a very quick action when i pinch it at full throttle to check the high end, but i heard you can also pinch it at idle and if it turns off in about 3 seconds AND transitions fine to full throttle your low end should be fine. any info on where i should pinch the to test the low end? between the high speed needle and the carb or between the line from the tank and the high speed since its a remote high speed needle?

RE: is my low speed needle broken? evolution 46
 

I have never used the low speed pinch so I am not sure where you would do that. I would presume at the same place as the high speed pinch.. but I can't be sure because I don't know.

I have a feeling that we are about to get educated, though.. :D

CGr.

RE: is my low speed needle broken? evolution 46
 

Pinch between the tank and the remote high speed needle.

The low speed pinch test can help determine if the low end is too rich and to see if there are any air leaks.

As stated the engine should continue to run for a couple of seconds or so once pinched, but it should NOT continue to run for say six or more seconds.

One thing with the Evolutions ( and almost any engine for that matter ), periodically check the nipple on the muffler to be sure that it is clear.

The gunk from the exhaust will often clog up the fitting, causing all sorts of tuning problems, etc.

It's a good idea to make this part of your preflight check.

RE: is my low speed needle broken? evolution 46
 

i actually checked the nipple yesterday and was clear but i'll keep an eye on it.

i'm guessing i need to adjust outside of the "safety net" evolution sets on the motors since it spits a bit of fuel when starting to rev up and will stay on for about 10 seconds after pinching the fuel line. it does transition pretty smoothly though.

RE: is my low speed needle broken? evolution 46
 

The line from the tank is fine for both. The key is patience, and make any changes small ones, and a little bit at a time. You will get it.

RE: is my low speed needle broken? evolution 46
 

Yup, on a couple of Evolutions I have the best setting for the engine is just past the point that the limters permit me to go... Ugh.

RE: is my low speed needle broken? evolution 46
 

Remove the limiters. They both come off easy.

RE: is my low speed needle broken? evolution 46
 

Yup SOP for me now.

I wish Evolution would just do away with them altogether and leave the engines with a better holder for the needles, so they do not "walk" with heat.

RE: is my low speed needle broken? evolution 46
 

thanks everyone for all the help and advice!