Evolution 45 PTS engine issues
 

Guys,

Have a brand new Alpha 40 with the Evo 45 trainer system. It flamed out day one right after takeoff at about 6 feet and caused a broken nose gear. I Removed the tank, checked the clunk, reassembled, reset the needles, and flew again. It cuts out at any bank or climb, but does not die. It is obviously running out of fuel, but I cannot figure why. It seems rich on the ground, spitting fuel out the exhaust. The clunk is attached and working properly as far as I can tell. Looks like the muffler pressure inlet has a small tube bent to the top of the tank. Whats this for? I fly helis and there is just a nipple going in the tank to pressurize it. I wonder if this is too tight to the the roof of the tank and is blocking exhaust pressure/flow from entering the the tank, causing a supply issue? Beyond that, I dont have a clue.

Any ideas?

Thanks!

RE: Evolution 45 PTS engine issues
 

It sound like you are running it to lean. Add about 1/8 of a turn more rich and try it.

CGr

RE: Evolution 45 PTS engine issues
 

If you have the adjusment limiters on the high and low speed needles, take them off. I have yet to see one of these engines come from the factory set in the correct range. Normally they're set so rich that when you go to throttle up they will burble and then die.

Brad

RE: Evolution 45 PTS engine issues
 

And adding to BKDavy's post... the friction clips also do not do a good job of keeping the needle valves from moving in flight too.

I've fixed many a PTS and Evolution engine by putting a piece of fuel tubing, or a grommet, over the clip to force them against the needle valve detents.

But those blue limiters HAVE to go!

DO NOT merely cut or rmove the limiter pin. Removing the pin but leaving the limiter on, has almost no effect.

The blue limiter is affixed to the needle valve and prevents it from moving in. Undo the blue limiter's grub screw, yank off the limiter, and send it to Evolution! ;)

RE: Evolution 45 PTS engine issues
 

I have just gone through everything.......................took the limiters off, checked all orings in the carb, checked the pipe baffle, checked the clunk, the lines, and the pressure inlet. The HSN was set at 1.5 turns, and I dont know about the low, as it was 4 3/4 from bottoming out with the slide out of the carb. I will reset to rough factory settings and retune. I dont think it was too rich, as it would pull to rpm everytime on the ground. It may have been a tad on the rich (safe) side, as its a brand new motor. it wouldnt have a tendency to get richer as you bank or climb, but leaner, right? The glow plug looks brand new, and the piston is spotless (no carbon, but its early).

How should the pressure line in the tank be setup with the copper tubing?

RE: Evolution 45 PTS engine issues
 

The walking needles that I talked about cause the engine's tuning to change in flight.

As you advance and retard the throttle the tuning changes on the LS needle.

The HS needle also may change because of vibration.

Evolution engines have a tendancy of becoming too rich in flight when the needles move. This can cause the motor to bog down in flight, and deadstick.

If the engine stumbles and quits at runup or takeoff, it may be too rich.

-

Muffler pressure is REQUIRED to increase the pressure in the tank, to assure even fuel flow.

One symptom of inadecuate or missing tank pressure, is what is occuring to your engine.

Make sure that there is nothing obstructing the muffler pressure nipple.

Take a clean piece of tubing and connect it to the tank pressure inlet. Disconnect the other line and route it to a cup or receptacle.

Blowing through the tubing should easily force fuel out of the tank on the other fuel line... You should feel very little resistance.

RE: Evolution 45 PTS engine issues
 

Problem solved!

Turned out to be the baffle in the pipe. Once I removed it, it ran like a champ. Made several flights on it with no further issues!:D

RE: Evolution 45 PTS engine issues
 

Excellent!

A lot of people remove the baffle to get more power from the engine at the expense of a bit more noise.

It sounds like it may have been producing too much back pressure in your case.