gmccord1970

Hi guys,

I bought a Magnum .52 two stroke and dropped it into a modeltech magic. This engine is a powerhouse. It ran great for about two gallons. I could hover the plane and then take off vertical like a shot at 3/4 throttle. However, I started running into a problem where the engine for some reason started to run hotter than normal and have poor transition from mid range to high end. In fact, I've noticed that the stock muffler that comes with the engine started to leak some black expended fuel around the metal sleeve. Now I can't hover vertical but the plane will fly well at level flight as long at it is not wide open. It will just dead stick if I throttle up to quick towards WOT. Is it possible that air is getting in through the side of the muffler and that it can make the engine run hotter and cause these problems? Has anyone else had a similar issue? Overall, I don't think Magnums are "hunk of junk" in my opinion and experience.

-G

asmund

Sounds like you have an airleak that leans out your mixture. Remove and put on some sealant compound around the back plate and the neck of the carb, also check if one of the two screws that holds the carb in place is missing or are loose, seal them too. Tighten up your muffler and verify that the pressure nipple is not loose and leaking pressure.

Remove the needle from the carb and blow through the passage to clear out any crud that could be restricting fuel flow thus leaning out your engine and causing it to run hot and deadstick.

If your engine ran great before and then suddenly starts acting up, then something is wrong, just have to find out what and fix it

If all of the above doesn`t cure the problem, I suspect you could use a new front bearing

Good luck, I hope you find the source to your problems

earlwb

Loosen up and retighten your head screws and maybe the backplate screws too.
The screws sometimes get a little loose after running a engine for a while. It isn't the screws coming unscrewed per se, but more about the cylinder sleeve getting bedded in to the crankcase and the head. As a engine heats up and cools off, the different parts actually move a slight bit (expansion and contraction) and get worn in a tiny bit. But is is enough to cause the head to come loose.

r007b66

My Feedback: (1)

I recently purchased one of these based on my past experience with Magnum engines. My first experience was frustrating to say the least. I used an engine stand for break in and within seconds the head started turning a greenish/ grayish color, so I shut it down immediately. I started searching the net and found this thread. I started off by tearing the engine down and did a pressure test to find many leaks. I then followed the recommendations by igotfish2 and sealed everything with blue high temp rtv including the backplate, carb base and the carb screws. I also used thread locker on all screws. I put the engine back on the stand and followed the tuning instructions that robert bauer posted. I ran the engine in this manner 3 more times leaning it out more each time but still running a little rich. I just flew with this engine this past weekend with absolutely no problems. I was able to idle for sustained periods and throttle up at will. I was also able to fly at mid throttle with absolutely no problems and throttle up or down at will. I will also add that I am running towers recommended plug, Omega 10% "pink" fuel, 11x7 prop, and a macs pre-tuned pipe for an os .46. This motor is still running a little on the rich side by choice and is turning 15000 rpm with this set-up. I believe if you take the time to follow these guys recommendations right out of the box you will be pleased.

langejazza

Hey, I bought one of these engines, brand new out the box, its run for approximately 2 hours solid, with richer settings. Put it in a Super Sports 40 size, 10% fuel, 11x6 prop , just for the heck of it, and it was a beast, turned this thing vertical and the plane nearly took off out my hand.

Now I have this problem, where the engine, wil not transition properly from idle to full, if I go too fast, the engine dies, nearly lost the plane because of this...[&:]

I have fiddled with this thing on a bench for what seems like hours, and it is still a devil, the engine seems to splutter, when I open it, so I lean out the low end. It then has this amazing habit of running, with a wide open carb but producing the power of a quarter throttle, I richen it and we are back to first base. This has been done with the top needle properly configured.

I have been flying for about 6 years now, but just with IRVINE Engines, until recently. I am at my wits end with this thing and would appreciate some help, before I end up using it as a paper weight.

Regards
Jarren

jimmyjames213

My Feedback: (2)

in my expierence with this engine, right out of the box it idles ok once you get it set, high end is good as well, the midrange is terrible and remains terrible till you have a few gallons through it then it fixes right up, becomes alot easier to tune and is a huge powerhouse.
.

gmccord1970

Lange,

Sorry for your frustration. [&o] I feel your pain. Been there done that as they say. My suggestion is this: as a rule of thumb, whenever I have an engine running well and then something happens where the engine is not performing I resist the temptation to mess with the engine. In other words, the problem might not be with the engine. Check your externals first....is your plumbing clear (fuel lines, tank, fuel filter etc. BTW, I had a magnum .52 that ran great and then I had a clogged fuel filter that produced the same EXACT problem has you described.) If plumbing is good, restore your low end and high end needle valve (usually 2 and half turns from closed) back to factory setting. Is your fuel contaminated? How's your glow plug? I always run an O.S. number 8 plug in my magnum engine BTW. If this fails, go to next level and ensure that all screws are tightened in the engine to prevent air leaks including the back plate, carb barrel neck, muffler neck and head bolts. You may want to put some RTV sealant as well. If all of these fail, then the last resort is send the sucker back to the manufacturer.

Good luck!!

-Geoff

langejazza

Hey, thanks, did some checking myself, and I realise I might have left out a few facts.
1. The engine never transitioned properly. but it had a mighty fine full throttle.
2. The plumbing was fine, everything was new...

I asked around and came out with two solutions
1. Pump fuel straight into the carbereutter, this cleans out any particles that could have entered the system, when fixing the fuel tubes etc.

2. Now this is the piece de la resistance: The carb does not need to be replaced. However having said that the golden key for me was to reset the secondary to about one and half turns out, instead of the factory preset of 3 turns. This is due to the fact that I live at an altitude of ~1500 meters above sea level, so the motor was running very rich (going down to see level means I richen it by ~1 turn out). THis explains why many people who bought a new carb finally saw the motor producing the right power(as OS carbs seem to be factory set to slightly leaner than my magnum one)

Now I have an engine that still needs to be properly run in, but produces so much power that I can take off at ~3/4 throttle, if not less. An I LOVE IT.

Any one in South Africa looking to get rid of these engines will find me more than willing to give them a new home: they are hobby engines, and a hobby means that we fiddle with things, for hours, its the nature of any hobby, especially this one, and I must say I learnt a lot getting this engine running, and am considered the nitro engine expert at my local field after all my research into the way these puppies work.

Thanks for all your help, gmccord1970. PS as an electronic engineer in training I truly appreciate the idea of leaving something that works alone.

Regards Jarren

NM2K

My Feedback: (14)

There are no consistently accurately set glow engine carburetors with "factory settings" manufactured in the world today, unless they are keeping them a big secret for some reason. Gasoline engines using Walbro carbs usually do have factory settings that are pretty consistent, but I've been bitten before after some moron decided to twist a needle just for comic effect. Therefore, I don't trust any engine's carb settings right out of the box. Listen to the more experienced guys at the flying field. You will never hear them refer to glow engine factory settings. The term has no meaning.

I'm trying to be helpful and to save many newbies lots and lots of frustration.


Ed Cregger

r007b66

My Feedback: (1)

For what it's worth I recently did some testing with my engine. I decided to try a theory I had looking at all the negative posts. I installed the stock muffler and immediately started having the issues everyone else is having with either good idle and no transition, or decent transition and no idle. I then reinstalled my macs pre-tuned pipe that i bought, that is for an OS 40/46SF and instantly I was able to smooth out the idle and have a perfect transition again. Not to mention I am able to throw an 11-7 prop at 15,000+. Based on this test I believe that there must be something this motor doesn't like about the stock muffler.

gmccord1970

Ed, I agree wholeheartedly that "factory setting" is really a misnomer. However, I was just pointing out that in order to eliminate variables to problem-solve one has to have a baseline benchmark on which to start from. I always was under the notion that "high end needle valve setting" was usually in the ball park between 2 and 3 turns from closed for most glow engines.

-Geoff

gmccord1970

That's interesting r007....A tuned pipe means you have more compression so I wonder if the issue with the stock muffler is back pressure, too much air???

blvdbuzzard

I did drill out the baffle inside the stock muffler to a #20 drill bit. I have the stock muffler and have not had much of a problem. Way back in the begging there were those that removed the baffle. I could have been lucky?



Buzz.

langejazza

Hey

By "Factory settings" I refer in specific to the settings specified in the manual that comes with the engine. Turns out that the shop I buy from has a policy of setting all engines to those settings by default, to cover there own ****** (still unsure as to why).

Sport_Pilot

You work at a model engine repair shop?  Why are you asking questions here?

NM2K

My Feedback: (14)

Again, I wouldn't depend upon even those factory settings. What if someone handles the engine in the shop and then changes those settings? There is no way to win this argument from my point of view. You should check the settings yourself and ensure that they meet the factory specs.

There are many folks flying glow engines today that make it much harder to do successfully than it truly has to be. I want those and every other, folks to succeed. Right off the bat. The way to succeed is to learn a few things right up front about glow engines.

1. You will not harm a glow engine by running it too rich. I'm not talking about turning it over when it is hydraulically locked up. I'm talking about it being able to run while spitting out a lot of fuel because the carb is set too rich. Won't hurt it. All it will do is produce less power than it might have when tuned properly and it will burn up a tank of fuel in a hurry. Both not the desired results that you were after.

2. The only way to learn how to tune a glow engine - is to tune a glow engine. Yes, you can learn a lot from reading, or talking about the subject from others, no doubt. Next to actually doing it yourself is to go to YouTube and look at the videos that show you folks running engines. I'll bet there are even a few videos that were made right from the start to teach someone how to get their engine going for the first time.

3. Since our engines are not alive, they have no will to make you look foolish or to hurt you. They are simple pieces of metal and plastic with no soul whatsoever. Save your anger and frustration for somone that deserves it. Your engine does not.

4. DO NOT flip the propeller with your bare fingers if you cannot afford a starter (electric). At the very least, use good, thick leather gloves on your starting hand and then find a suitable stick with which to flip the propeller. All sizes of our engines are quite capable of severing nerves with the result that you may lose precise control of your hand. I am a musician, a touch typist, a draftsman, a model builder, a bassist, a guitarist, an artist (drawing) and I build electronic circuitry by hand. I'm sure there is more, but the point is, each of these have been affected by injuries that I have sustained while starting model engines by hand. I no longer hand start my engines.

5. And watch those electric motors! Those rascals can hurt you just as badly as any glow engine.


Ed Cregger

Sport_Pilot

Chicken sticks feel akward at first, but that is no reason to give up on them.  After a while they will seem natural.

jessiej

I have tried them off and on for the last twenty years or so. Maybe they will feel natural in the next day or so.

jess

bret191

And don't forget that the crank case is PRESSURIZED while started even thow there is a time of negative pressure in the cycle but over all while running a slight positive pressure!! That is why some use the crank case as a pressure port for a smoke system or fuel pressure port. They use this pressure to LUBRICATE the bearings. Oil is constantly be Pushed OUT of the crank cavity all-bet SLOWLY when working correctly and not worn out. Ah the simplisates of a 2 stroke.

bw5493

My Feedback: (36)

We race this engine and the stable mate ASP .52 in our SPAD DasPlasSticks, running club 40 2 pylon, and have great luck. The motors are cheap, reliable and very powerful and fast. For everyday sport flying, the Master Airscrew 11x7.5 is king, and for racing, the APC 10x8 is the preferred set up. Hot plugs are a must, and we run 15% nitro, 20% oil fuels, with the Sig Champion 1/2 Castor 1/2 klotz being the best performing.
The bearings are junk, so We swap out the bearings for the Boca $11.99 ones, and have even bought new sleeve and pistons from hobbyking. After break in on a stand at a crackling 2/4 stroke for a tank, running it a WOT rich 2 stoke for 4 tanks before putting it in a plane is a must on a 10x7 or 10x8. Once in the plane, get your high needle set, then set the low end, using the pinch test and that works on 97% of the engines we have dealt with, only had to mess with the needles on a couple. Out runs the OS 55 on the same prop, but will only see 8-9 minutes of run time on a 8 ounce tank. The .55 OS will get a lot better mileage at around 12+ minutes. The Magnum/ASP seem tuned for higher RPM and the .52will slightly pull away from a OS 55, so races are usually won in the turns.

A side note for installing the Boca Bearings..your engine will now not spit fuel all over the engine any more. The factory set up spews fuel all over the darn place, and your motor will be soaked from the front bearing. With it sealed up, the engine is a real dynamo. So if you dont want yours, feel free to send it to me..we'll make sure it gets a good home in a plastic racer!!

iskandar taib

My Feedback: (5)

What we used to do with them was back-flip the engines. Prime the engine, turn it over 2-3 times, then turn the engine counter-clockwise until the exhaust port closes and it bumps up against compression. Hook up the plug, then whack the prop in the OTHER direction (clockwise). The engine will bounce against the compression and start. We used this technique to get one flip starts in Fast and Slow Combat. I'd still use it except it would feel awkward doing this with a model between the legs (which is the way we start them in F2D). That and F2D props are a little more fragile than Scimitar 8x6s.

Iskandar