Hi everyone.. I am new to nitro engines and had a couple questions.

I have a GMS .47 engine and am trying to tune properly..

The low idle needle valve requires a clockwise motion to increase or open the valve. I know this because it used to shut off at idle until I turned it clockwise.

The question is.. which way is RICHER OR LEANER on the high speed needle valve.

I would guess its the opposite of the low needle valve.

Guessing that turning the knob counter-clockwise would make it richer while turning clockwise would make it leaner..


What do you think?

Thanks!!<br type="_moz" />

If it is a normal needle valve, clockwise would lean the engine out. Good Luck, Dave

Both high-speed and low-speed needle valves do this:

Clockwise is less fuel == leaner

CCW is richer.

This is true for all glow engines that have two needle valves (like the picture).

Some lower cost carbs have an air bleed instead of Low speed NV. the air bleed screw works opposite. Opening it up (CCW) lets in more air and makes the mixture leaner.

I have never heard of an NV (low or High) that turned clockwise to open. More than likely your low end was rich, which was causing the engine to quit at idle. When you turned it CW, you leaned it to it's proper position.

Normally, either side is clockwise to close, CCW to open

wow.. Thanks for such the quick responses.. very much appreciated.

I can say for certain that from 1/4 throttle to full throttle, it ran fine. no problems getting to those high RPM's quickly and with not much sputtering..

high end was not an issue..

and i was really getting pissed because on this GMS was just getting worse as I turned the low speed idle CCW.. Shortly after I started turning it CW it started to run much better.. it idled well and then went to wide open very nicely..

I justdidn'tknow for sure which way the high speed turned to make it richer/leaner..

I still think as I did originally that the high speed CCW is richer and CW is leaner..

Why the low speed is opposite, I don't know..

maybe because it is a "cheaper" motor, the post above may apply..

Thanks.
Pete

Either way , thanks much for the commenting!!

Pete

The picture that you have posted doesn't correspond to the carburetor of your engine.
The one in the picture has a little hole at front for air intake thru the low end bolt.

If your carburetor is this one:

http://www3.towerhobbies.com/cgi-bin...&I=LXEGK8&P=RF

You have two needles that control the flow of fuel.

Study this information:

http://www.blacksheepclub.org/tuning.htm

Copied from that link at Tower Hobbies:

"Adjustable control on a carburetor used to set proper fuel/air mixture. Some carburetors have separate needle adjustments for low and high throttle. Typically, turning the needle clockwise (screwing in) leans the mixture (less fuel), and vice versa. However, there are a few exceptions - refer to the engine instructions."

To properly set the high speed needle:

Open the throttle to full speed. Turn the needle in until the engine runs smoothly. BRIEFLY pinch the fuel supply line. If the engine:
1. Sags immediately, it's too lean.
2. Speeds up and holds speed, it's too rich.
3. Speeds up briefly, then begins to die, it's about right.

I just thought I'd throw this in.

How I remember which way to turn the needle valves is: Unscrewing it makes more room for the fuel to go through so that makes it richer and screwing it in makes less room so that makes it leaner.

I recently had fits trying to get my GMS-47 to run well after messing with the needles too much. I ended up going back and starting from scratch using the settings from the manual.

With the engine off (duh) and the throttle wide open, adjust the LSN until the gap is 2mm. I used a 2mm allen wrench as a guage. Then close the HSN valve (whichever direction makes it go IN) and back it out 1.5 turns.

After I did this, it fired up and ran perfectly. Just pay attention to which direction you are turning each needle so you can make small adustments afterwards.

Good luck

Or in super-technical terms - Righty-Tighty, Lefty-Loosey

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Or in super-technical terms - Righty-Tighty, Lefty-Loosey
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Thats how I remember it!!!