schutter

im new to planes if been all heli's up to this point but I have a new Alpha .40 running the stock Evo engine in it, i have started it a couple times in garage and run it up seem to work good off the start, now when trying to throttle up it wants to stall out on me. Im running, cool power 15%. i dont wanna start playing with the needles much yet cause i dont want to make problems worse.

MetallicaJunkie

try opening the low end in small increments till it transitions smoothly

jester_s1

Does it die when you try to take off and the plane is moving, or does it die in testing? If it's the former, check that your clunk line hasn't come off in the tank. If the latter, just do some searching on engine tuning. It's not a complicated procedure if the tank, lines, and engine parts are sealed up with bolts tight.

jetmech05

if it idles ok and bogs down or starts to die on power up then your too rich on the low end...lean the low end a little at a time

MinnFlyer

My Feedback: (4)

Do this:

1. Remove the blue collar from the Low End needle

2. Open the barrel 1mm (one Millimeter)

3. Close the Low End needle and re-open it 1 1/5 (One and one fifth) turns

4. Replace the blue collar centered between the stops.

This is how they SHOULD be set up at the factory, but many of them seem to slip by with a different setting.

mscic-RCU

My Feedback: (6)

If it were me I would leave the blue idiot collar off!

MetallicaJunkie

when it stalls on you is it "coughing and spitting" or does it die almost immediately?

opjose

Amen to both of the prior two posts above MetallicaJunkie's.

Blue Collar = Ca-Ca....

Remove them and you end up with a nice reliable engine.

schutter

Thanks to all for replys,

Well i tried removing the Blue collar on the low end, and did the 1 1/5 turn, i ended up close to 1 1/2 and it seems to be running ok but it still shuts down unpredicatblly some time only at low-mid stick, (no air bubbles in line). My hign needdle i havent touched a whole lot yet but its near factory setting right now. So once i get it to Half stick no problems it will throttle in that range no problems, but in low-mid wants to bog, But only sometimes??? so its definatly running better but i dont wanna get it in the air till im sure!, Thanks.

Also The engine will run in either Clock wise/or counter clockwise position?? only good in the correct way but i didnt know that was possible till now!! Im starting it by hand for now, i got a starter on the way, but by hand its like 50/50 which way it starts for me some reason.

bingo field

When it starts backward, it is overly rich or choked, that is all. After you get used to starting this engine, you will have a feel for just how much to choke it when cold to get it started. I know the engine is supposed to be already "broken in", but the truth is, it could use more running, and you are doing the right thing by taking care of the tuning on the ground, as it will never get better in the air. Once you have run a couple more tanks of fuel through it on the ground, you might want to start carefully (as in slowly) tuning it.
You can probably forgo the process of blowing through the fuel line, as it already starts for you, but this is if you get anything really screwed up, and need to start from scratch.

The following proceedure works well for starters.


How to setup the needles so you can get your engine started.

Remember the following rules about needles:

1. Low end needle affects the mixture below 1/2 throttle for most engines. Use it to adjust the idle and the transition from idle to full throtttle.
2. High end needle affects mixture above 1/2 throttle. Adjust it so engine is running 300-400 rpm shy of max lean rpm at wide open throttle.


Start by opening the high end needle about 4 turns from fully closed. This is just a starting point to ensure the high end needle valve isn't restricting fuel to the carb so you can adjust the low end needle setting.

The low end is easily set to a good starting point with the following procedure:

Close low end needle valve completely.

Install a clean piece of fuel tubing into carb fitting, make sure it is long enough for you to blow into it with your mouth.

Open carb to 1/5 open from closed position

Blow into fuel tubing while slowly opening up the low end needle valve. Stop turning low needle valve when you first feel air blowing into carb from your mouth or hear the sound of air blowing into carb. The flow should be restrictive and very small. We only want a small amount of fuel to flow (air to flow) at 1/5 throttle opening. This low end needle setting will get your engine running and may require further adjustment. THis is just a ball park setting.

Now close high end needle valve and open carb to full throttle. Blow in fuel tubing and simulataneously open high end needle until you have FREE FLOW of air into carb. You should not experience as much resistance to airpressure as you did on the low end. Your needle valve should be open between 2-5 turns (it all depends on the carb folks).

This procedure gurantees you don't have a blocked carb or closed needle settings for low and high. This will get you in the ballpark which then will require you to fine tune your low end and high end for best performancehighly recommend the pinch test .

Start engine and use the following procedure to fine tune your engine once it is running and warmed up:
Pinch test procedure:

First start engine this way:

Prime engine by opening up throttle to full and blocking exhaust with finger. With blocked exhaust, rotate engine until fuel just enter's the carb-watch fuel line to see fuel displacing the air in the fuel line.

Reduce throttle from full to about 1/5 throttle opening. Apply glow ignitor and rotate engine (hopefully w/ starter) counterclockwise (for 99% of all engines out there) until engine starts. When engine starts, move throttle to 1/2 throttle and then remove glow driver.

If engine won't start, try more throttle until it does. If engine will only start above 1/2 throttle, it means your initial low end needle setting was too lean. Richen it about an 1/8th of a turn until the engine starts at a low throttle (1/5 throttle) setting.

If engine will not advance to 1/2 throttle when glow driver is on then leave at 1/5 throttle with glow driver until engine is warmed up-about 2 minutes should do the trick.

Advance throttle again to 1/2 throttle slowly. If engine dies then your low end needle is probabably too lean. Richen by 1/10 increments.

Once you can get your engine running at 1/2 throttle then its time to remove the glow driver/ignitor. With ignitor removed, advance throttle to full throttle. Chances are your engine will be too rich and may even quit. If so, briefly pinch and release fuel line as you advance to full throttle to verify the mixture is too rich. If it is too rich, then in small increments lean it out until it will run at full throttle without quitting. This does not mean the high end mixture needle is set. This is just a starting point to ensure your engine is running at wide open throttle (WOT) so you can make the proper adjustments.

With engine running at full throttle, slowly and carefully lean the high end needle valve until the engine is spinning at its max rpm. This can easily be determined by sound alone-no tach needed. This is where engine is producing most power but the mixture setting will cause the engine to run too hot and overheat. So, as a safety feature, always richen the mixture about 300 rpm shy of max lean rpm. Verify this by briefly pinching and releasing the fuel line to the carb. If the pinch test causes the engine to speed up and back down, then you have correctly set your high end needle setting. If engine doesn't speed up much or dies then you are still to lean and need to riche the mixture slightly until it passes the pinch test.

You are almost there. With high end needle setting set about 300 rpm rich of max lean rpm, recheck idle and transition. Let engine idle for 30-60 seconds and then snap throttle to WOT. If engine hestitates in the transition, fine tune mixture so that the transition is snappy and idle is reliable. I personally like a lean idle mixture so I can idle for long periods without fuel pooling up in the crankcase which causes stumbles when transitioning to full throtttle. You can also use the pinch test when the engine is idleing. Pinch and hold fuel line with engine at a fast idle. Engine should speed up and die about 4 seconds. If it takes longer, your low end needle is too rich, if it takes less time or if your engine dies instantly, you are to lean and need to richen your low end needle. After every adjustment to the low end mixture, you must recheck the high end mixture. Otherwise you don't get the correct settings, and the next time you check your high speed needle, you'll screw up the low end.

Once low end needle is set, you will probably never have to adjust it again. However, your high end needle should be checked before every flight by doing the pinch test at WOT to verify the mixture is slightly rich. This 5 second test and adjustment, if necessary, will gurantee you a reliablie engine that will last a long time. Our carbs do not adjust for changes in temperature, humidity, barometric pressure, etc... and a small change of 5 degrees in temp can cause a properly tuned carb to be out of tune and possibly too lean (or too rich depending on whether it gets hot or cold outside).

Hope this essay helps the newcomers to our hobby and prevents them from becoming one of the set it and forget it crowds that do not benefit from optimum tuning for the best engine performance and longevity out of an engine.



PS An engine may not idle or transition as it should when it is new and not fully broken in. Use these instructions to get your engine started and then do the appropriate break in (rich 2 stroke if it is an ABC type engine or even richer if it is a ringed engine or 4 stroke engine).

bkdavy

My Feedback: (1)

So far good advice, but one piece is missing. There's no point in doing anything with the low end needle until you've adjusted the high speed needle. You have to set the high speed a little rich of peak before you can do anything with the low needle. Then after every adjustment of the low end, you have to reset the high end. Both needles work together, and only changing the low end without checking the high end will just lead to frustration. Trying to learn how to do it based on advice from internet forums is difficult at best, so you might want to find a local person that knows how to do it and get them to help. A tachometer can also be useful, but not required.

Brad

MinnFlyer

My Feedback: (4)

As bkdavy said, you need to set the high-spped needle before adjusting the low end.

However, you said you went one and one-half turns on the low end. That is probably why it is loading up and running backward.

Set it to one and one fifth, start the engine, adjust the hight end (Again, you may need to remove the stop) and see how it runs