I have an Evo 46 from an xtra easy 2 in my Avistar. When I go from idle to full throttle there is a slight hesitation but the engine runs just fine aother than that. Is it a lean or rich problem or something to do with the glow plug. Thanks in advance.

T/A

I have the same engine and have the hesitation too...

And i have to really lean out my high end needle to get the most power.

My engine used to be so nice, then the humidity rolled in and my engine took a dump on me...

Turn your low end idle screw IN 1/8 or 1/4 turn and see if that helps. Then readjust the main needle valve.

Randy,
I think these engines have an "air bleed" type carb. If this is the case then you need to turn the air bleed screw OUT a little to lean the low end.

But I agree with the advice. You need to lean the low end slightly to ge rid of the hesitation.
Dennis-

Does the engine also have trouble shutting off right away? If yes, then the hesitation could also be caused by an air leak around the carb body where it enters the engine. To fix this, pull out the black hex screw hoding the carb in place and smear a small amount of automotive silicone sealant around the body of the carb and on the screw then reassemble. it does wonders. Use ULTRA GREY,BLUE or COPPER. I had the same problem you describe and it was both in need of a low end needle adjustment and air leak sealing. Now it runs better then when new.

Are you slamming the throttle wide open, or rapidly advancing it? My .45 Evo will take the sudden throttle opening, but the .46NT doesn't seem to like it. It gets better with each tank of fuel.

The .46NT low speed needle valve leans with clockwise turning.

As the humidity (water vapor in the air) increases, the percentage of oxygen in a volume of air decreases. This causes your engine to run slightly rich. On a foggy day, it can get really bad. You probably need to touch up the low end by leaning it out slightly, 1/8 turn in or less on the mixture screw. The problem with adjusting for an occasional high humidity day is you have to adjust back when the air gets less humid. If I have a really good running engine, on one of those low clouds, "the fog has just lifted", really humid days, I tweak the high end and accept the low end so I don't have to reset the next weekend.

If the engine is new, it also will get better with more running. I have an Evo .46 and after a gallon of fuel, they are easier to keep adjusted. They are partially broken in at the factory and run well out of the box, but they aren't completely freed up. As you get more running time, you'll have to adjust less.

Some engines will never lose the slight hesitation. I haven't noticed this on my Evo.

This engine has a duel needle carb. The low speed needle is to rich. It only takes a small change to correct it. The low speep needle is on the right looking down from the top. Dennis

I had to adjust mine leaner than the factory set low needle range allowed. Thsi finally got rid of the hesitation, but I had about 4 or 5 hours on it before I could get it to idle for an extended period and still transition to WOT smoothly.

Don't be afraid to do this, but make small adjustments. To adjust it, just loosen the set screw on the ring around the low needle and turn it in (or out to richen) 1/8th. tighten the set screw and see what it does. Repeat as necessary.

On a side note, I converted mine to needle on the carb after crashing my Twist and breaking off the remote needle bracket. Only thing is now the fuel nipple position is terrible.

Duke

Thankyou all for the replies. I will have to remove the stop on the low end to adjust it any further lean. I live in Utah at 46oo feet so I will bet that it is just too rich for this altitude. Thanks

T/A

My .45 Evo runs like a bat out of h*ll no matter what the weather is. Fog, humidity, dry weather, it doesn't matter to that one. I never adjust it unless I'm just curious. I've learned to leave it alone and keep slamming the throttle open a lot if I fly my trainer. It never quits, hesitates, or bogs down.

About my .46NT- that engine had more power on the first takeoff than the .46FX and TT Pro .46 that had been on the same plane. A couple of us who were familiar with the plane were surprised. The NT keeps getting better and better like Ed said. I would put the .45 on another plane with an APC 11x7 if it weren't so heavy. I think it is around 7 ounces heavier than the .46 NT.