The engine starts no problems and will idle fine. When I go full throttle it revs up but then loses power and dies. I let it idle for a while but still no improvement.

Is this a new engine? First time running?

It is new but has about three tanks through it including 15 minutes of flying.

Sounds like its lean on the high speed needle or, maybe, your fuel tank is too low or, you have some other fuel system problem.

You might have to remove the limiter pins on both needles so you have more adjustment. They just pull out with a pliers.

Check your clunk line and vent. Are they in the right position?

I have this same engine. Its been fine but not overly powerful for a .46.

My GMS .40 makes more power.

Keep fiddling. You'll figure it out. I think its a pretty good engine overall.

Dave

Yup sounds like it's lean on the high end.

Hmm I find that the Evo .46 produces MORE power than the GMS .40 ( I have both, not that the .40 is a wimpy engine ). Something may be amiss.


The Evo needles tend to "walk" when the engine heats up.

It's worthwhile to remove the pins -AND- the blue collars, and then pull out the clips, tighten them down and re-install...

Why remove the collars and not just the pins?

The collars have a grub screw that holds the collar to the needle. These get overtightened at the factory to the point that the metal of the needle is deformed enough to tightly bind the collar to the needle even when the grub screw is removed.

That means that the blue collar will continue to act as a limiter of sorts, preventing you from moving the needle IN ( leaner ) any more than it was originally set to at the factory... even with the grub screw removed! ugh.... found this out the hard way.

oh for a os

I found that with all my Evo. motors,tighten up the clip and removed the pins and now their great,and a lot easier to tune
Cheers

It's an Evo, that's the problem.

Given that its flown, if it was revving up to full throttle, but has suddenly started dieing, which is what it sounds like, you may have something clogging the needle valve. I've seen this several times on new planes.

The first and easiest fix is to hook up your fuel pump to the outlet from the needle valve, and pump fuel through the needle in the reverse direction. This will normally flush out any contamination. Make sure you don't just pump it back to the tank.

If that fixes it, put a filter on your fuel jug and on your fuel line.

Brad

No, that's not the problem. I've always loved OS Engines, but I have 3 Evos and they are all excellent.

But I agree with others, the limiters have to go.

In any case, you may be too lean, OR too rich.

Have you tried adjusting the needle valve when it is starting to die?

One other thing, from left field.
You didn't per chance have a somewhat hard landing after that 15 minute flight?
If so hold the nose up and shake the plane, your clunk line could be stuck in the front of the tank pinching the fuel line.
Just a thought.

The landing was smooth and was done by my instructor. I live about 40 miles from my instructor/field and I won't see them until next week. Hoping to figure this out prior to flight night so I don't waste valuable training time on engine issues. The clunk moves around freely. It seems this engine has not run correctly from the start as my instructor and another guy had to fiddle with it a lot last week before flying. It seemed to be ok after that during flight. Afterwards I drained the remaining fuel and went home. Now it does this. My other new Evo .46nt has been awesome. Always starts on the first flip of the prop and runs smoothly.

I will look into the needle limiters although I am not sure what I need to remove. By the name I assume it is the stoppers on the needle valves that keep it from turning further.

The engine has BLUE anodized aluminum collars on both the high and low speed needles.

The collars have a black metal pin.


The Collars are secured with a small hex grub screw.

Loosen the grub screw and pull the collar straight up. If what I describe has happened, this may be difficult to do.

Once the collars are off, remove BOTH the high and low speed needles.

Before you do so make sure you COUNT the number of 1/2 turns you can screw the needles in until they "bottom" lightly, with the engine at full idle position on the throttle. Write this down.

Now remove both needles.

Removing the high speed needle will now permit you to remove the friction clip.

Take it out and bend the tines in to provide MORE friction when you re-install the needle.

Put it back in all the way, then count the number of turns as you restore it to where it was.

On the low speed needle, take a microdrop applicator and apply Loctite BLUE to the threads.

Then screw the low speed needle back in fully, then back it out to where it was before.

This will prevent the low speed needle from "walking" as it tends to do, when the engine heats up.

DO NOT get Loctite on the grommets, only on the threads. While the needles are out, blow out any obstructions from the passageways and check for debris.

Opjose, When you say "loosen the grub screw and pull the collar straight up" do you mean straight out as in slide it off. The collar is round and impossible to pull up.
Can you or someone

I am about ready to smash this damn thing.

Yup you want to slide it completely off.

If it is present, even if you remove the black PIN it will still prevent the needle from moving further in!

Get rid of it. Apply threadlock to the low speed needle to prevent "walking". Then tune the engine as normal.

Be sure to tighten all the cap screws on the engine and the high speed needle valve assembly too. These will loosen once the engine is run once or twice.

Well That helped him solve his problem.

EVOLUTION.

By the way that is not the .46 it is the .45 Trainer.

Specs

Type: 2-stroke
Displacement: .45 cu in
Bore: .87 in
Stroke: .77 in
Cylinders: Single
Total Weight: 19.52 oz
Engine (Only) Weight: 16.32 oz
Muffler Weight: 3.20 oz
Crankshaft Threads: 1/4 x 28
Benchmark Prop: 10x4
RPM Range: 2,000-16,000 rpm
Fuel: 10% - 30% Nitro
Mounting Dimensions: 44mm x 17.5mm
Muffler Type: Cast
Cylinder Type: ABC

Yeah, and you were no help either. BTW the one that is labled as a .46 is actually a .47 and neither is actually an Evo. They are Evolution engines.
Evo engines are entirely different and made in Spain.
http://www.evo-engines.com/

The one he has in the picture is a .45, I Don't Recall Saying the .46 was a .46 and I also Don't recall calling it a Evo. I think I recall saying EVOLUTION. & I also don't recall Quoting you. Read before you type.

I GUESS that you couldn't figure out that not ALL of my comments were aimed directly at YOU but at the general tone of the thread as well. A wealth of non-helpful comments, including mine up to a point. I apologize for crediting you with the ability to discern the difference between comments directed toward you and comments directed toward the "thread" in general. I now understand your limitations and will be careful not to exceed them. Have a nice evening.

I also apologize to you for not knowing that you did not have the ability to direct your statements properly. I will take that into consideration next time & try to understand what you are saying & to who. Have a nice evening.

Hmmm, He must of got it fixed , since this thread has been dead for 3 months , either that or he got a new engine.

Bruce, Minn..

I've posted my reasons for disliking the EVO's in other forums. I thought I would have a good engine at a reasonable cost, even bought three of them. But all of them would not perform and EVO people were no help. Send it to us, they said, and we can see what's wrong. I sent them one and they told me it was ok, so when I got it back, it would still not run. I had a 100 on an Excelleron 90 and it never, not once in six months, was able to burn a complete tank of fuel in a flight. It always quit in flight, not always at the same time or during the same maneuver. At times, I would take off, make a turn, level out then it quit.

One suggestion was to buy and install an OS carb. Ok.. at $80.00 plus the cost of the engine, well, it was then approaching the cost of an OS. So, I just get the OS and am done with it.

I just don't like them and will say so because I've had it with them. After almost a year of struggling with them, I think I am entitled to my opinion about them. If people have good luck with them, ok. I can appreciate that, but I clearly did not. Even my Super Tiger, with the leaking carb, broken muffler issues, and all, ran much better than any of the three Evo's.

There have been several different threads about the problems with EVO's in the past few years, there are three in the past few days in the beginners forum, yet I don't recall any about the OS or Super Tigre, or others that are quite as repetitive as this.

I've not been totally negative about ideas on how to fix the problems. See http://www.rcuniverse.com/forum/m_6525680/tm.htm and see my posts and you will note that I thought several 'fixes' had merit. I don't own the engines any more so I can't try the fixes. But, I believe, as I said, that they may have merit and those with the engines and are still having problems, may want to give them a try. I just didn't want to rehash all that again in this particular (or probably any more in the future) thread.

CGr.

Well what everyone has been saying might be true BUT if you live in a high altitude, your answer is you need to lean out the engine a bit. I dont know why but it worked for me. I didnt adjust it my flight instructor did.

But if you live at or near sea level, and they still don't run, well, you may do as I did. I got rid of them and went directly back to OS engines. Never regretted it.