Summer Carb Adjustment.
 

Hello All,

I have a quick question.

I fly in Las Vegas and it's starting to get HOT! Should I richen or lean out the needle on my carborator? What about the low end ajdustment?
Last time out it would fly good for a while then when it comes time to land or non-aggresive flying it wants to die and I must dead stick the landing.
I have been flying for just over a year.
I'm flyinf an OS 1.20 in an edge 540 that has a few(3-4)Gallons of fuel(Master 15% nitro with 18% oil) through it and I add 1-2 oz. castor to it.
Thanks ahead of time.

Mike

RE: Summer Carb Adjustment.
 

You'll tend to go a little leaner in the summer because the air is less dense. Obsessive types may actually go down one step in the heat of the plug or reduce the nitro a little, but I don't bother with that. As for setting the low end, heat isn't going to affect it much, so get a good idle and transition and leave it alone. On all my engines, if they won't idle for at least 30 seconds and then go immediately to full throttle, I don't fly.

RE: Summer Carb Adjustment.
 

Jester said it well. Anytime there is less oxygen available, then the fuel mixture needs to be decreased. That is why some fliers think that their newest fuel is better in cold wx, or worse in warm weather, same as going from 1000 ft elevation to a 2000 ft or more. One just has to tune the machine. Like you, once you get above 10-12000 ft. your energy tends to wane. 18000 ft. MSL, is 1/2 atmosphere and it drops quickly as one climbs.

RE: Summer Carb Adjustment.
 

As a local desert rat in Vegas that has been flying here for a few years I know from season to season where my needles will be. I use YS engines and every one of them will start out in the summer perfectly, once set I don't change the needles until our weather starts to drop from our 100 plus degrees. At about 60 degrees I have to open up the high end one click. At about 40 another click and by the time we get into the mid 20s I will have the engines about 4 clicks fatter. The difference doesn't seem to change on the low end so it is almost never touched. We are now in the 90s so I have been leaning them out again as needed. Your OS may react a bit different but it shouldn't be much.

RE: Summer Carb Adjustment.
 

I will try to lean it out a bit next time out.
The neeedle valve is about 1-1/4 turns out and still has a proper smoke trail. Does this sound about right for this engine?
Thanks again for all of your advice.

RE: Summer Carb Adjustment.
 

There is no way to say what the right needle settings should be for a given engine. Tank position, fuel mix, local density altitude, and the quirks of your individual engine all play a role in what the right needle setting will be.

RE: Summer Carb Adjustment.
 

It is what it is, no one can say. Each engine will be different. Ever see the needle twisters? Those are the guys at the field that will twist the needles before each flight. I don't play that game, if the engine ran well last week it will run the same this week. I make a bit of change if I put on a new prop of a different size and as our weather starts changing. With our weather it is a very slow change from summer to winter. Last weekend it was 98 and today it is colder and over cast, it isn't enough to bother the engines enough to twist a needle. Last month I took out a plane that hasn't flown in a year, my only two stroke, it ran perfectly without any adjustment. Like Jester pointed out, there can be a lot of little things to make engines all run a bit different. Just changing fuel brands can do it. Just tune your engine the way you want it then leave it alone. Come fall it will change a tad. It doesn't care if it is 90 or 115 in our climate but it will change from now and when it is in the 60s. Mine don't like to start first thing in the morning when we get into the 30s and 40s.

RE: Summer Carb Adjustment.
 

Thanks for all your help. </p>

RE: Summer Carb Adjustment.
 

I don't know about that, Gene. [X(] At about 40 degrees, my needles are set the way they were before it dropped down that low and stay that way, along with the plane, in the hanger, until the weather changes to the point where it's over 50 degrees.... ;)

RE: Summer Carb Adjustment.
 

[&:] Needle twisters. ENJOY !!! RED