northriver21

My Feedback: (1)

I am using the Evolution TPS that comes on the Alpha trainer.
I have been using it for several months with no problems, but lately it has been acting up.

It will start up and run great for about 45 seconds and then just die without warning. I dont think its to lean because there is plenty of smoke coming out of the exaust. The last six flights have been deadstick landings.

I have tried different glow plugs and that did not work.

I have noticed some small air bubbles in the line between the remote needle valve and the carb
so I removed the tank and inspected it and the fuel lines, but did not notice anything wrong with either. Are a small amount of air bubbles acceptable?

I have tried tuning the high end and then removed the limiter on the low end to tune that. I could not get it to transition within the low end needle limiter settings. It would load up and die most of the time.

I had it transitioning perfect in the garage high end sounded good and it idled nice and didnt sag when going to full throttle.

I took it out to fly today thinking the problem was fixed, but it started acting the same again. It would load up,so I would lean it out then it would run fine ,but die in the air.

It seem like this engine runs fine in the garage, or when the temperature outside is warm, but when it gets colder it wont stay running the temp today was around 30.

I need some suggestions I am fairly new to engine tuning, and this is the first time I've had trouble with the Evolution. I have had several of them with no problems.

I am afraid of removing the neddle limiters and getting it too lean.
where would be a good place to start over with the needle settings?

My fuel is almost one year old could that be the problem?

I hope I am describing this with enough detail to diagnose the problem, if not ask me a question and I will try to answer.

Any help would be appreciated.

KidVermin

My Feedback: (3)

In cold weather, I use 15% nitro and no lower than 10% as it gets warmer. I try to store my fuel in a cool, dry and dark location. I've noticed a year old jug does cause more problems than fresh with the red plug in place.
It might be as simple as a new gallon and up the octane.

northriver21

My Feedback: (1)

Thanks, Im using 15% and I'm righ to the bottom of this gallon.
I have some more fuel on the way from tower it should be here any day
I will try that.

xchangx

My Feedback: (2)

northriver21... I have a quick question for you. My 3 blade prop broke as I hit a tree landing (didn't look like my plane was out that far). I read on the review on this board that the Evolution .46 engine came with 2 kinds of flywheels.

One with the stabilizer (weight) and one without. However my Alpha didn't...

Are you using a 2 blade prop? And if so, how did you get a spinner on with the flywheel.

I called Horizon and they said that I would have to leave the weighted flywheel on and not use a spinner.

Thanks!

5_spot

My Feedback: (1)

northriver21,when i took my plane to the airfield it started without problems but they tuned the high and left the low setting alone,they were surprised it ran so good from the factory,the first time he took it up it died and he came in on a dead stick,something about using full throttle,next time he used half throttle a few times til he got it high enough then started giving it more throttle,everything worked out.
good luck

DBCherry

My Feedback: (4)

I'd suggest replacing the fuel lines, especially from the carb to the tank. (Clunk line too.)

Any bubbles in the line feeding the carb means you're getting air in there somehow, and it will cause lean runs (and dead sticks). Try it first, because I'm fairly sure that's the problem. (It could also be fuel foaming in the tank, but....)
Dennis-

bhole74

Check if there are any air bubbles between the tank and needle valve or just between the needle valve and carb. If there are no bubbles leading up to it but there are after it, you need to replace your needle valve o-ring.

FHHuber

I'm in the habit of putting appz 1/3 inch of fuel tube over my needle valves as an extra seal. The O-rings seem to always start leaking after a month or two of using the engines.

This particulr case sounds like some mixxed indications.... he says he's got the smokyt appearance of adequate fuel... then its dieing in a manner that usually indicated its gone lean. Could be the idle is set rich enough that he gets a few seconds of running from fuel accumulated in the crankcase. That would give these results.

The air bubbles after the needle but not between the tank and needle is positive indication of an air leak. Air leaks are ALWAYS bigger problems at higher throttle settings. Cure the air leak.

northriver21

My Feedback: (1)

I think you guys are on the right track.

Now that you mention it I did not notice any air bubbles between the tank and the needle.
I will replace the lines in and from the tank, but as for changing the o rings in the needle.
Is that somthing I should attempt myself? Should I send it in to have it serviced?

I will run it again and watch closer for air between the tank and needle.
If there is air there also, do you think I have to much vibration? should I balence the prop again and see if the tank is foaming?

Does anyone think the older fuel is my problem?

When I run the engine in the garage, I cant get it to die on a long run. It seems to only do it when it is running outside and its cold.

I would tend to belive that the o rings are bad because I live in Alaska and I bring this plane out from warm to cold regularly. That would cause o rings to fail.

Any more suggestions? I am planning on working on this today.

Montague

How does the fuel look? Is it nice and clear like it was when new, or does it have a kind of cloudy look? It can't hurt to try new fuel, and if it's been sitting for a long period in a half-empty jug, it's quite possibly bad. However, bad fuel usually shows up at idle first, the high end usually isn't as sensitive to old fuel.

I agree with Dennis, I think it's a pin hole in the fuel lines allowing air in. Those pin holes can be sneaky, they are really hard to see, and they can open and close with vibration, causing all kinds of headaches.

I'm not sure if I'm reading you right, but it sounds like the engine runs fine on the ground, but dies in the air. Have you tried running a bit more of a tank on the ground at the field? Try filling the tank only half way, and running it on the ground. Do a lift test, pointing the nose up while at full throttle on the ground. See what that does.

Oh, and we have guys here using the flywheel and a standard two-bladed prop and spinner. The spinner backplate works fine with the flywheel there, as long as you buy a spinner with a flat backplate, some are recessed, while other's are flat, it's a brand thing.

DBCherry

My Feedback: (4)

I didn't read your original post closely enough, so I'll modify my advice.

If you do NOT see air bubbles between the tank and remote needle valve, then replacing the tank lines probably won't do anything. So check the bubble location(s) first. If they are only after the needle, then the above advice is likely correct. The "O" Ring on the needle is bad. As FH mentioned, placing a piece of fuel tubing over the needle could well correct it.

The line between the needle and carb could still have a pinhole in it, so if the tubing over the needle doesn't work, replace that.

As Kirk mentioned, be sure to hold the nose of the plane up at full throttle to be sure you're not set too lean. I've found that I have to run my engines quite a bit richer in cold weather.

One Other Thought!
Depending on HOW cold it is, the cold air could also be cooling the engine too much in flight, which will put out the glow plug. So you might also try wrapping a little aluminum foil around the cooling fins on the head.

Good luck,
Dennis-

Homebrewer

My Feedback: (8)

There's nothing wrong with your engine. Some engines are not very friendly to use in cold weather. All my MDS engines run like a champ in warm weather but run like carp during our annual news years winter fun fly.

RCaillouet3

DBCherry is right on, if you have any bubbles in the fuel line, you need to correct it. Repalcing the fule lines is a start. Checking the o-rings are another good area.

Cold running engine could be the culprit as well. A hotter glow plug may be the ticket.

Another thing I would reccomend though is to buy a NEW gallon of fuel and try it. I have heard stories of fuel going bad after it has been exposed to long. An example of this was from a friend having the same problem. But what he was doing was bringing the fuel to the field, then right into his house. The outside temp was around 30 degrees, inside was about 75. This cause the air to heat up and let some condensation into the gas, or at least it is what I speculted to. He bought a new gallon of gas, had to retune the engine due to the tuning measures he was attempting with the bad fuel, and the engine purred!

Summed up: Check fuel lines for air leaks (replacing may be a cheap measure to this,) change to hotter runnning glow plug, and getting new gallon of fuel would all be areas to check into first.

Just my thoughts,

Reg

northriver21

My Feedback: (1)

First of all thank you guys for the input.

This is what Ive done so far. I replaced the stopper, and fuel lines in and from the tank.
I happened to have a fuel tank from an alpha that I crashed last summer, so I took out the stopper and fuel lines and put them in the new plane.

I also replaced the line between the needle and carb. I just used regular fuel line (I hope thats right), it looks much thicker than the original line that was there to start with, but the ID looked the same.

I will wait for my new fuel to arrive and then start over with the mixture settings.
If the air bubbles are gone I will try a hotter plug.
Can anyone reccomend a hot plug that will fit this engine?

If that doesnt work, and I will try the aluminum foil.
If I still have air bubbles and nothing else works I will send it in for service.

I have to find a way to make this engine run good in cool temperature or else I'm SOL living in Alaska.

Thanks for the help so far I will let you know how it goes.

Montague

I haven't done that on the Evo engine, but I've used standard fuel tubing between the remote needle and the carb on my OS .25FX's and it worked fine. They also came with smaller OD tubing like you describe.

Live Wire

GLOW plugs. carbon build up .

5_spot

My Feedback: (1)

I was working on my plane this morning and had to move the fuel line,the one between the carb and needle,i moved it a little and it broke off at the needle fitting,i didn't have any of the small line so i used larger od but still the same id and it seems to be a lot better.

Spaceclam

it sounds like it is seizing up to me. two strokes will smoke a lot anyway just because they are burning oil and they are, well, two strokes. what oil percentage are you running? you should use around 20% on those two strokes. The reason i think it may be seizing up is when the temp gets too high, without warning, the tolorances of the sleeve get so close that it clamps down on the piston and causes it to stop running. try going to a higher oil percentage. keep in mind, if it is seizing up it will eventually ruin the engine.

Montague

5_spot, if the line broke just from moving it, that would likely have been sucking in air for quite a while, it doesn't take much, that's for sure.

As for seizing, the Evo engines are ABC, so, actually, the piston-liner fit gets LOOSER as the engine heats up, because the liner expands faster than the piston. So, overheating won't hurt the piston-liner, it will just cause the engine to slow up and loose power, but won't hurt it or seize up. (However, in theory you could cause the conrod or other parts to seize, but if you do that, the result would be a broken engine, I'd think. I've seen broken rods, and other bits but never just from running hot. And I've overheated my share of engines). Also, believe it or not, some engines will run cooler with less oil, while others want more. 18-20% oil is pretty safe for most engines and most oil blends. Some oils work better than others, so you can use less, some engines need more oil than others. I wouldn't bother running a new Evo on anything higher than 20% oil, and 18% should be just fine.

Also, when an ABC engine over heats, it doesn't just quit all of a sudden. You get a drop in power and rough running for a couple of seconds, it takes a little time to get over temp. (I had a long battle with engine overheating on one of my planes a while back. finally fixed it with a helicopter-style heatsink head and some much bigger holes in the cowl. It was a "long" battle because I REALLY didn't want to cut up the cowl like I finally had to). Oh, and you usually have to really work at it to get a non-cowled engine to overheat. I'm talking seroiusly lean running.

Now, if you had a ringed engine, over heating and seizing up the piston is absolutely possible and very very bad, almost instant paperweight.

Btw, if you can track back a source of air bubbles to something besides fuel tubing, you can often seal things up with RTV silicon, available at autoparts stores (get the high temp stuff, obviously). I've used it around fuel tank stoppers, on fuel fittings, carbs (espeically where the carb mounts on the crankcase) and remote needle fittings etc. Works great. Oh, you can't "fix" fuel tubing, just replace it if there is any doubt. Tubing is cheap.

On final thing I forgot before, I've seen the Alpha's fuel tank split at the stopper a few times. Once it filled a guy's fuse full of fuel. Other times, it just caused the engine to run poorly. If you haven't already, pull the tank and inspect around the stopper. You can do a tank pressure test by putting it in a sink full of water, with the fuel lines out of the water of course (no water inside the tank please). Then plug one line and blow in the other, then pinch it off. Look for bubbles. If you see any, fix it until you don't anymore .

Spaceclam

the evo engines are abc? COOL. i never knew that.

northriver21

My Feedback: (1)

Ok, I am working on this right now.
Like I said earlier,I replaced all of the fuel lines, and no air bubbles while running it on the garage floor.

It is running very rich, lots of smoke and fuel coming out of the exauhst.
How many turns out should I start at the low end?

When I turn the plane up at a 45 deg angle and then level it out, just like if I were taking off.
I get a huge air bubble between the tank and the needle valve.
The engine does not die, but thats because I think I have it running so rich.

What next? I am trying to get this worked out now, thanks.

5_spot

My Feedback: (1)

I'm new at this and have no idea where the settings are but try this,give the engine full throttle and let it run for 30 seconds for warm-up,then adjust the high until it bogs down then back a quarter turn,let it idle then go to full throttle,if the engine hesitates turn the low end screw out 1/16 of a turn at a time until it doesn't bog down,if it's cold it will probably bog down tho.Then back to full throttle and adjust the high again,let it idle and if it hesitates going to full throttle,then richen low 1/16 turn until it revvs up smooth.The air bubble has something to do with the pickup line in the tank,one thing you might try is going to a smaller id line from tank to needle .Just a thought but others will have inputs as well.

RCaillouet3

The air bubbles could be from a number of places. First thing I would check is the tank! Do you have a split at the stopper section would be most likely. Second, do you have a bad stopper? This is not very common, but occasionally you get one that allows a small bit of air through. Third, have you tried replacing the pick up line inside of the tank? Lastly, have you tried new line from tank to needle?

If the tank is okay, the first thing I would do would be to open the tank and replace the pickup fuel line. Second reseat the stopper and only after the stopper is seated fully,coat the front of the tank near the stopper and the stopper area with a silicone sealant of some sort. This may not end any leaks at the stopper section, but will go a long way to keeping them from being big problems. Then I would replace the fuel line from the stopper to the needle valve with a quality fuel line.

Once you have done with this the air bubbles should be either gone, or at least lessened.

Now a small, key word is SMALL, amount of air bubbles will not generally due much harm. It will generally make the engine run a little more lean, but with a rich needle setting you should be okay. The key thing is to check for a CONSISTENT engine run. You want to have an engine that will run without the worry of it stopping suddlenly all the time! As long as you can get the engine to run consistent and well, a SMALL amount of air bubbles won't hurt much.

Just my thoughts,

Reg

Spaceclam

it sounds like your clunk may have come off. if you rotate the plane and what not the fuel will shift becuase it is liquid. the clunk weighs enough to bent the tube to wherever it needs to go, but if it came off, the tube is somewhat rigid and it may be sucking air that way. it is also possible that your pickup line has come off, which is why it sucks air when it is turned. check it for us.
cheers

Montague

If you hold it at a nose-up and leave it there, what happens? It sounds like you went nose-up then back to level fairly quickly. Leave it nose up for a while and see what happens. And instead of a 45degree, try straight up. The engine should be able to pull fuel striaght up while at full throttle.

It does sound like what the other guys said, a problem inside the tank with the clunk line, either the clunk came off the line, or there's a hole in the clunk line, or the line is off the tank's tubing or something along those lines. My money is on a hole in the clunk line where it attaches to the tank's tubing. I've had this happen plenty of times myself, usually due to being sloppy putting the tank together.

The Alpha tanks are known for leaking. It seems that sometimes they over-tighten the stoppers at the factory, causing the tank to split.

Here's an idea if you don't feel like pulling the tank out right now. Go get another fuel tank and strap it to the side of the fuse and test run the engine using that external tank. If you can do a left test and whatnot with that tank, but not the one in the airplane, then you know where the problem is.