low speed needle
 

i'm having real dramas tring to run my engine below half throtle since screwing with thelow needle?????????[>:]

RE: low speed needle
 

poolittle, what engine are you having problems with ?
Bill

RE: low speed needle
 

A few more details would help.

Why did you change it? Had it been running fine and then started to act up?

Which direction did you move it?

How far?

Which engine, prop, glow plug, and fuel?

Did you reset the high speed needle between each low speed adjustment?

How much fuel has been run through the engine?

All these details are important to be able to try to point you in the right direction.

Brad

RE: low speed needle
 

I have no idea what engine it is but in general, for me especially if it a completely unknow engine which I've run across more than I'd of ever thought I could

first set the high end by setting it to full thottle, peak the RPM then back it off about 500 rpm with the high needle.

get the engine to the lowest possible run you can then pintch the fuel line hard for like 3-4 seconds. if it speeds up and dies it's too rich. if it just stops it's lean. righty-tity is leaning lefty loosy richens it.

get it going and lower the idle somemore and pitch it again. again does it speed up or just die. keep doing this until you can give it a good pintch with little change using 1/8 of a turn at a time.

Then richen it about a 1/4 turn

now reset the high end and recheck the low end. it will speed up very little.

RE: low speed needle
 

Unless its an air bleed carb.

This process also presupposes that its not a glow plug going bad or a hole in the fuel line hence my first question of why adjust it in the first place. If the engine was running fine, and then started giving trouble, first suspect is always the glow plug, then the fuel lines, then the tuning, in that order. Trying to tune the low end with a bad glow plug or air leak in the lines will only lead to frustration.

1/4 turn is much to large and adjustment on the low end, particularly if your getting close. 1/8 turn or less should be the rule. Otherwise, you'll miss the sweet spot.

Brad

RE: low speed needle
 

it's a saito .56gk i messed with it at the start cause i'm an idiot it still idles beaut if power is atached im waiting on a tacho now i think before i have a nother go what do you rekon?

RE: low speed needle
 

Let me see if I understand this correctly. It idles great when it has power, but dies when you remove it? Assuming the glow plug is good, this usually means you've got the idle set too rich. How does it do at full throttle with the power removed?

Here's a quick guide to setting the needle.

You should always set the high speed needle first. Only after you have this correct should you begin to work on the low speed needle.

Setting the high speed needle on a 4 stroke requires a bit more care than on a 2 stroke because the change in tone as it goes from slightly rich to peak and then lean is less obvious. However, the difference can be heard. If necessary, use a tachometer as a visual guide. I always set my high speed needle slightly rich. Once I've got it where I think it's right, I point the nose of the plane straight up. If the engine starts to sag, it's way too lean. Lower it and richen the high speed needle. If it keeps the same speed, I consider it a bit too lean still, so I richen it a bit and try again. If the speed increases a bit when I first raise the nose, but then stays steady for 10-15 seconds, I consider it good to go. And finally, if there's a big increase in speed when I first raise the nose, it's probably richer than it needs to be.

After you've got the high speed needle set, it's time to work on the low speed. You said you've changed the setting from the original. Fortunately, all is not lost. The Saito manual tells you how to get the low speed needle close to the original factory setting. In case you don't have it, here's a link: http://www.horizonhobby.com/ProdInfo...ER_2005_10.pdf . On page 10 is says to set the idle needle to the point where the head is flush with the throttle arm housing.

Once you've reset the needle to the original setting, here's a little trick I learned to get the needle close to right. With the power still attached, run the engine up to full throttle to clear out the carb. Then bring it back down to idle for a few seconds. Once the idle has stabilized, remove the power. If the engine slows considerably, the low speed needle is too rich. If it doesn't slow at all, it may be too lean. I suspect the reason this little test works is because when the engine is too rich, the extra fuel hits the glow plug element. While the power is on, the battery helps keep the element glowing, but once it's removed, the wire is cooled and the engine slows. Once you've got it close, you can fine tune to ensure that you've got good transition.