ZoomZoom-RCU

OK, guys. I've been fooling with this issue for over three weeks and have gotten nowhere. Thought maybe some of the experts in here might shed some light on it. I've been having trouble with reliably hand starting my Magnum XL 52 4-stroke. Its turning (or poorly attempting to) a 11x7 prop. I'm using 10% nitro and hand cranking it with a chicken stick. Here's the wierd thing. It used to start (although sporadically) after a ridiculous amount of cranking, and run ok. My goal was to get it to start more reliably. It improved somewhat and, a few times it fired very easily from the back stroke...bumping it in the wrong direction and it firing on the kickback in the right direction, and that even on the first couple flips. I'm improving I thought! Riiiiight. Anyway, after a few runs (maybe 5) like this, it has stopped starting altogether. It will sputter and turn over a few times on the crank at best, and this very reliably, but never really start. Only sputter-tick over a few turns and die. I've tried everything. I pulled the valve cover and checked the gaps, you can get a shim of flashing aluminum in the gap. I don't have a gap tetser but it seems both gaps are the same, so they probably haven't moved. I tried all of the nuts and bolts to be sure nothings loose. All seems good. There don't seem to be any air/fuel leaks. My glow plug seems to have a touch of brown film, but I've cleaned it off with no improvement. I think its due to unburned fuel from all of the sputtering no-starts.Anyway, I'm stumped. You guys have any suggestions before I pitch it off a bridge?! This is my first foray into 4-strokes, and, as it stands, I may not be coming back. [:'(]

TIA for the help!

ZZ.

The Ghost

First the prop is wrong (too small). Read the instructions that came with the engine and use the settings that are in it. Are you using an OS 'F' plug. When checking the tappet clearence you should only use the correct feeler gauge(check the INSTRUCTIONS) and only need to be looked at after run in. Some 4strokers will need an electric starter untill it is run in and high and low needles are set. Also you will need a tacho to set the max RPM as you will not be able to hear the peak.

Cheers

ZoomZoom-RCU

Sorry Ghost, I meant 12x7 for the prop. So what I'm using is whats recommended. And the glow plug is a 4-stroke plug, but I'm not sure if its the same as the OS-F you recommend. Will that matter? I have a miracle plug, for 2 AND 4 stroke I could replace it with. As for the rest I haven't altered anything from factory, so it should be ok. Thanks for the suggestions.

ZZ.

Scar

My Feedback: (3)

Mine's inverted, in a World Models Ultimate 30. I prefer a 12X6 APC, and am using a Thunderbolt 4-stroke glow plug I got from Hobbyshack (now Hobby People.) And, I like using an electric starter, because I can't get at the carb to prime it.

The ones I've started by hand, I like to prime & then work the fuel a bit by turning the prop over briskly about six times. Then I turn it backwards up against compression and attach the glow driver. I let it sit perhaps 20 to 30 seconds, warming up the fuel/air mix in the combustion chamber, and then roll it 180 degrees forward direction, and slap the prop backwards. It hits compression, ignites and runs in the proper direction. (usually.)

If yours doesn't, start changing things, like the fuel jug, the glow plug, the fuel delivery system. There are engine guys who won't look at your engine on the plane, they want it on a test stand (where they can see & control the fuel tank & lines.) Might be a good idea to start there.

Good luck,
Dave Olson

ZoomZoom-RCU

Thanks Scar. Thats an interesting proceedure, and I will try it. I'm new to 4-stroke so its all an unknown to me. To prime do you cover the exhaust and crank the prop? How many times? I've been blowing in the pressure return from the muffler till I hear it gurgle in the engine, then turn it through 4-5 cranks. Im worried about flooding it, but don't think I am cause it won't even try to fire unless I do this. I can't use an electric syarter in my config....so I'm gonna have to make it work somehow.

ZZ.

P.S. I think you have a clue in your proceedure there, cause I've noticed a tendancy to kick a bit more on the back stroke when its been allowed to sit a bit before cranking it. Hmmmm.

Rodney

The easiest way to prime is as you say here, cover the exhaust and turn the engine over (holding the prop firmly so it doesn't backfire and cut your fingers) a few times. Mine like to start a little wet but; if mounted inverted, be careful not to get a fuel lock or you may break or bend the con rod. When I use an electric starter, I do not even prime first, just put the igniter on and apply the starter. Most of mine, once warmed up or properly primed, will start with a simple reverse flick by grabbing the spinner between thumb and finger and give a sharp clockwise (backward) snap. It kicks and starts in the proper direction.

The Ghost

Check out [link=http://saito-engines.info/throttle_setup.html]Saito Setup[/link] I know that you don't have a Satio engine but the information is simmilar for all 4strokers.

Cheers

ZoomZoom-RCU

Thanks guys for all the help. I've tried all the above for over three weeks with no improvement. All I can say is its a Magnum POS, and I am done with it. Guess in this case you get what you pay for, and the reduced dollar sign lured me in and I got bitten on this one. Sooooo, anyone here have any experience with the OS-56a? Easy to hand start? Run on 10% nitro? All my OS engines are great, so I'm thinking, go with proven reliability and ease of use. Any ideas?

ZZ.

cracker

Sounds like your needle valves are not adjusted properly. Put them back at the factory setting and follow the break in procedure. This engine takes a little bit to break in. I have 1 and it runs excellent. You will need a starter for this engine. Run it as recommended and lean the settings according to the instructions. These engines IMHO are not a pos. I have several magnums and they run as well as more expensive ones. You will like it once it is broke in and adjusted properly.

ZoomZoom-RCU

Appreciate the attempt at rescuing Magnums good name, but it doesn't cut it here. I tried every needle valve combo possible including first and foremost thier factory settings repeatedly!! Annnd, what part of I CANT USE an electric Starter doesn't get across. So, since Magnums seem to be waaaaaay too finnicky to allow ease of hand starting, much less reliability in finding a needle valve setting that can be maintained......(or startable!!), I'm going in a higher quality direction, and recommend others do the same. Unless of course they have thiers mounted on a flying plank where they can electric start it and fiddle with the settings all day. I'd rather fly...thanks. My confidence in thier product is shot, and in addition to this, I now have to replace the bottom of the fuselage in a brand new AC where it spewed gunk and fuel from maybe 1000 failed start attempts. No thanks, I'm done. Perhaps I was just unlucky and got a lemon, even so...my 4th chance drawer is empty. The Os 56fsa is lookin pretty good right now.

ZZ.

khelsea

I have one on my Cap 232, the second plane. It starts and runs excellent but I do use an electric starter. Follow this thread and give it time to breakin, you'll like it. Khelsea

khelsea

And get it back on the engne stand till you get it figured out, you have something wrong and need to eliminate the possibilitys. Khelsea

ZoomZoom-RCU

This has already been done. Its heading back to Magnum today, for the SECOND time, for repair...then I'm selling it. You got $120.00? it can be yours!!

ZZ.

Seriously

TFF

I have never had much luck hand starting a 4 stroke even though I see it done all the time at the club; 2 strokes easy. I only started my Mag .91 one time by hand as my old flying buddy was not with me and I was at a new club. They felt sorry for me and lent me a starter for the day. Every other 4 stroke I have I have never tried to hand start. That .91 is 7 years old and runs great, not the same quality as an OS or Saito but it is 93.5% as good. I think the secret to getting a 4 stroke to start by hand is to get it truly flooded, but I am too scared for my fingers and face to do that, and the ones who do hand start theirs seem to to it rather franticly not methodically.

ZoomZoom-RCU

Thanks TFF. I'm hoping that extra 6.5% quality boost will make the difference with the OS! I've read a few articles regarding the 56FSa, and they all indicate ease of hand crank starting. I've sure gotten enough cranking practice with the Magnum, so it should be an improvement.

ZZ.

Scar

My Feedback: (3)

Just out of curiosity.... did you ever try the (previously mentioned) checking it out on an engine stand? On an engine stand, you CAN use an electric starter, and control the fuel feed, ect.

What DID you try? Different fuel? Different glow plug / driver? Turning the setup upside down? All these, and electric starter use, are straightforward in a test stand.

If you have the same problems with that OS, try running it on an engine stand.

Good luck,
Dave Olson

ZoomZoom-RCU

Thanks Scar. Yeah I tried pretty much all of the above mentioned, except maybe the upside down thing. Didn't see a real point to that, but oh well. Thing is I had already sent this thing to Magnum once before cause the valves were sticking, and wouldn't stop. And this was just when hand cranking it over before I even fired it up the first time, so, afraid was I that there was something internally wrong, I sent it in to have it checked out. They did this, and ran break in runs before they sent it back....so it should be beyond any "difficult intitial" break in area. I'm aware that after a few gallons things change further, but at this point, and for my purposes, this is unacceptable, and I don't think there will be similar problems with the OS. I chose poorly. Magnums are not known to hand start well, I should've determined this before I bought it. There are also numerous threads on the difficulty of tuning these reliably. I've found that to be dead-on in first hand experience, and for someone who has specific needs from a 4-stroke that it must meet, this isn't a good combo. If your a fiddler and tweaker who likes constantly playing with something to keep it "in tune", this may be your deal. Its not mine, and on top of it, I know there is something wrong with this one. Anyway, thanks for the assistance and I'll let you know how the Os works out. From what I've read its worth the extra $ for my scale purposes. And, if anyone wants a newly serviced Magnum 52 for around $100.00, let me know...cause it must go!!

ZZ.

Jonathan Ott

My Feedback: (25)

Zoom-Zoom, another "just out of curiousity" question: Why can't you use an electric starter? If it's 'cause you don't have one, I understand. But if you are in a club, ther has to be others around that have an electric starter that could give you a start when you are out at the field. Again, I'm just curious. An electric starter is a good investment if you are planning on staying in this hobby and flying glow engines...wel worth the ~$20 they cost (at Tower Hobbies).

Jon

ZoomZoom-RCU

If you actually read through any of my previous posts you will see that I mention numerous times that this is a scale model, and due to this fact it CANNOT BE STARTED WITH AN ELECTRIC STARTER. This is due to the type of spinner it uses. I have one, but actually haven't used it for YEARS cause all the rest of my engines are actually not POS's. Sorry for my small vent. I understand you are trying to be helpfull, and I truly do appreciate that.

ZZ.

B.L.E.

Two things are critical to sucessfully useing the back flip method for starting four strokes.

First, the engine has to be well primed.

Second, the throttle has to be nearly closed, idle or slightly fast idle.

Also, make sure your glow plug battery is well charged, you want the plug to glow yellow, not just red.

Jonathan Ott

My Feedback: (25)

ZZ...actually, in this particular thread, there is no mention of the airplane in which this engine is mounted. I'm not going to read the other ~450 posts in your count to find out what plane you have this on.

Now, if you are using a Carbon Fiber or Fiberglass spinner in a scale application, I can understand why you cannot/will not use the starter. But, you know, if I'm unable to get my engine started for initial break-in and tuning, just because I have a spinner on there that precludes me from using the starter, that spinner is coming off unitl I have the engine broken in and set to a point where I can hand start it reliably, then the scale "ain't gonna use it with an electric starter" spinner can go back on.

I also understand the trials and tribulations that users go through with the Magnum engines. I've had 'em myself with a .52 2-stroke...little b@$tard would not start or run unless I had the cylinder head pointed up. I had it on a profile plane, side mounted, so you can understand the heartburn I had having to stand it on a wingtip to get it runnng. Turned out the fuel I had (that was new from the LHS) was actualy old and had no pop left in it. New tank of fuel from a buddies jug and that bad boy was running like a top.

I'm sure someone will be interested in buying your Magnum for their application. Good luck with the new OS. I hear they are great engines. (I'm a Saito guy myself, when I have 4-strokes in the hangar)

Take care, and don't let it get you all in a knot. It's a hobby, remember?

jaka

Hi!
First a 12x7 is too much prop in most cases for a .52-.56 four stroke.You should be using a 12x6 prop. APC or RAM are good props
if you want to use a smaller diameter or larger diameter prop it could be done but most of the time a 12x6 is the prop size that will work best.
You should also be using an OS F glow plug and fuel containing 5-15% nitro.
Tank size 8oz. No bigger. Best tank is a Tettra "Bubbleless tank" and next best is a "Uni-flow tank using two clunks, where one is for pressure the other to the carb as usual.
If using a normal tank (not a Tettra bubbleless) it has to be placed right. Which means having the tank centerline in line with the carb fuel intake orrifice. very important´!
Hand starting is no problem if you follow these rekommendations.

ZoomZoom-RCU

Thanks Exteme Aero, I understand completely. As far as the "read previous" was concerned, without having to read every post I've ever listed, I simply stated in this very thread that due to it being in a scale model, electric starting was out. You are right, I do have a composite spinner, and an electric starter would destroy it. Since the engine was already broken in at Magnum's service center, I got to the point where I realized.....if it won't crank in this config now, its never gonna. Jaka.....I'm staying calm....people.....READ. I used a 12x6 prop that is exactly what is recommended by the manufacturer as an acceptable size...and read further you will see I've already stated that I've used the proper glow plugs. And hand starting waaaaaaaaaaas still a problem. Accept the simple fact that Magnum's SUCK at this. Or at least this one did. Anyhoo, this link speaks for itself.

http://www.youtube.com/watch?v=v9QWivsed4w

ZZ.

TFF

With your set up problem no matter what engine you end up with, you will have to bench break it in, or if you have too in the plane, remove the spinner and run it in; as the last place you want a new engine in where you cant experiment to get it right. Because it is in a scale plane, it would be foolish to do anything but. On the side, I have a new scale plane and my starter wont spin the engine cold, so out came the chicken stick and I proceded to knock off the fake radial engine. Yea! Should have benched run that one too.

ZoomZoom-RCU

Totally true TFF. I learned that one the hard way. Thats one of the other things that irks me about Magnum, other than the fact I should've done my homework better before buying one, thier manual essentially says, there's no need to use a test stand, these engines are so reliable/well made that the best place to break your new motor in is in the plane. What a Crock. Once again, yeah perhaps if its a plastic drain pipe trainer with the engine hanging out the front where you can tweak it every few seconds/ look for air leaks/pull it apart etc etc etc... Live and Learn. You gets what you pays for.

ZZ.

PS....From now on I'll use the test stand, even with the OS56a, and it'll be purring before that engine gets anywhere near my plane.