AirWizard

My Feedback: (3)

I have a new 3W 55i that has about 2 gallons of fuel run threw it, The problem I'm having is that it will not idle down. Sometimes when I pull back quickly from full throttle it will slow down and die. Other times when I pull it down slowly from full throttle it will only fast idle. Transition is good. Sorry for not explaining it better.

Anyone have any ideas what my problem is?

bubbagates

My Feedback: (32)

what kind of throttle connection are you using, It should be stiff like metal or carbon fiber rod. Nylon or sonething flexable can also cause this as the heat changes it's length and any flex will make it inconsistent.

It could also be a throttle servo problem

AirWizard

My Feedback: (3)

The pushrod is metal 4-40. The servo is a digital Hitec 5625MG

bubbagates

My Feedback: (32)

David,

I actually had the same problem and it ended up being two things. I used a semi flexable rod and it was vibrating to the point the it seemed that I could never quite get the idle to work well. It seemed that a single click of the trim was either too fast or slow enough to kill it, but only after I flew it. I changed the rod and it got better but then I noticed that after a really hard flight my trim needed two more clicks below where I took off from.

After some thinking I decided to cut a small air intake whole which was directly in line with the first 3 fins below the spark plug and since then I have had no problems. BTW, this is on an Aeroworks Yak. The cowl is wide open but the top 1/3rd of the head is blocked by the bottom of the cowl. Basically the cutout is at the bottom of the cowl in the cowl ring, kinda looks like a smiley face, the mouth part

AirWizard

My Feedback: (3)

Bill

I have the engine installed on a Lanier Edge 540. Are you suggesting that the engine needs more air?

bubbagates

My Feedback: (32)

I am suggesting that but I have a feeling that you are getting enough air. Through checking with an infared temp gun. I have found that the hottest part of the head is between the 2nd and 3rd fin below the spark plug. If you are not getting airflow to those fins then you could be seeing heat related problems.

Does everything you explained happen in the air or on the ground, after a flight, during a flight or during a flight when the plane is in a certain spot like Knfie Edge, inverted, etc or before a flight. Maybe with that kind of detail I can help you figure it out.

I do undersdtand what you are saying about what is happeneing but I am not exactly sure what is causing it short of a servo not returning to center or the throttle plate is loose on shaft, or the throttle shaft itself is loose, espically since you are using a metal control rod

Did you leave the throttle return spring connected, or did you remove it completely or did you just disconnect it. Almost every gas engine requires you to leave the spring on but just disconnect it from the arm as the spring also acts as a spacer for th4e trottle plate/shaft and if removed it can allow the plate to not close all the way under certain conditions.

Sorry if I am covering things you may already be aware of

AirWizard

My Feedback: (3)

This happens both on the ground and in the air. I have not removed the spring or disconnected it.

No problem.....I'm looking at everything

marc morin

My Feedback: (1)

I had a similar problem with high idle speed ,my timming was advanced to much I set it so that the center of the magnet on the prop hub was exactly in the middle of the 3W on the ignition pick up at TDC.never ran so good .Idles really low with excellent acceleration.

AirWizard

My Feedback: (3)

Marc,

I checked my TDC against the center of the pickup and my magnet is slightly to the right of center. I assume you are talking about the red magnet?

marc morin

My Feedback: (1)

Thats correct .Draw a line with a marker from the center of the red magnet out towards the prop so that it is visible when the magnet is under the pick up .My engine was out by 1/8 " adjusted and now she idles sweet .