4 stroke engine problems
 

I have a os FL 70, not the surpass 70!!! The engine is mounted upside down and holds and idle horribly but idles wonderfully with the glowplug is on. I have long lost the stock air-bleed setting from messing around with it. I emailed OS and the guy said that becuase the engine is upside down, fuel puddles at the glow plug, killing the engine. He said I would benefite from an onboard glow starter which makes sence to me. I was just wondering were i could get one of these. I was also thinking though, wouldn't the glow starter stay on all the time, thus burning up your reciever battery really fast. A friend told me that a onboard glow starter could be set so the glowplug turns on at idle but shots of at higher throttle settings. Is this true, becuase man that would work out great. Any advice please?

RE: 4 stroke engine problems
 

Your friend is right Cambo. If you decide to get an onboard glow, make sure the battery that comes with it is at least 1100 mAh. The kind I have has a pilot light that you can mount in the cockpit to observe when the glow is working. Mine Y's into the throttle servo and can be adjusted to only come on at idle.

RE: 4 stroke engine problems
 

Tim is right. I use a 1400 mA Nicad set to come on when I get to about 1/4 throttle. I use micro switches I "borrowed" from the Navy but you can get them from Radio Shack. Most of my four cycles don't need it and placement of the tank makes all the difference that and using a hot plug (enya #3 is what I use in all my 4 cycles). I very seldom flame out at idle in my inverted engines but it only takes once to bend an airplane. On board ignition is cheap insurance. As far as fuel puddling in the plug area at idle, I find that hard to believe. The engine is turning at about 2200 rpm and the fuel would never have a chance to fill that area plus it's HOT in there and it would vaporize. That's just my opinion though.

RE: 4 stroke engine problems
 

All of the current on board glow systems use a separate battery to power them and only run at idle. This cut in and out function is adjustable on most glow drivers. How does the engine run right side up? Are you using an OS F plug? Are you using the correct fuel and is the engine tuned properly. I would make sure and then invest in an onoard glow system. There is a weight penalty, cost, work involved in adding one of these systems. On an old motor, It may be more trouble then its worth. :eek:

RE: 4 stroke engine problems
 

I make my own from an old servo and a micro switch and wire the servo into a Y harness with the throtle then use a servo wheel ground to the shape of a cam an ajust it to come on at 1/4 to1/3 throtle. I have purchased a 4400 mil nicad and this system works great.I tried two of those comercial drivers and they didn't work so I made my own!

RE: 4 stroke engine problems
 

Sorry, misunderstood, fl70 is a current generation 4 stroke. strike alot of what I just said.[&o]

RE: 4 stroke engine problems
 

Man, some fast replies, thanks alot. I just thought of trying to tune the engine rightside up. I will try that first. Can someone post a link to were i can get one of these glowstarters also. I am pretty sure that tower hobbies sells one but it involves soltering some connections. I would like to avoid that since i am not the best solterer in the world.
Also what type of fuel should I be running.

RE: 4 stroke engine problems
 

Ya it is a type f glow plug

RE: 4 stroke engine problems
 

Yes low@slow, from what I've learned here at RCU, an air-bleed carb can be a bear when the engine is inverted. I've never tried it though. rctrax, that is a very good tip about grinding a servo wheel into an eccentric to operate a micro-switch. How did you grind it?

RE: 4 stroke engine problems
 

Cambo, here is a link to the brand I'm using. I bought the one with a smaller battery than this one and ended up changing it to a bigger battery. There is no soldering with this one. I would imagine 15% nitro would be the best for that 70.
http://www2.towerhobbies.com/cgi-bin...P?&C=PDC&V=RAM

RE: 4 stroke engine problems
 

TimC, will i have to buy the 29 dollar charger for it or can i use the wall outlet charger that i use for my nicad reciever battery. I was looking down at the requirments and it said you need to buy a servo extension and remove the male end for charging. I gues there is no charge end? What does this mean? I gues i will also need to buy Y harness to attach to the throttle servo. Do the instructions explain how to hook it up into my electical system.

RE: 4 stroke engine problems
 

I made mine out of stuff I had around my shop. The most expensive thing was the cell. If you have a Du-bro glow driver you can use its charger to charge the cell if it is a 1400 mil sub-c or you can use the charger for the D size glow driver. A battery holder and switch from radio shack are cheap.

RE: 4 stroke engine problems
 

Cambo, what I did was change to a female Universal type end for charging the sub C cells with my Hobbico Elite. I see from looking at my system that I left the 800 mAh sub C in the glow starter and paralleled another 2000 mAh battery to this one. If I had it to do again, I would go with the simple Y harness from the throttle channel on my receiver to another servo/ micro-switch like rctrax described. You could use your glow lighter charger to charge the battery for your onboard glow if you bought the right terminal. These are available with wires for remote glow uses. You really need to be able to solder; it's not hard at all. Cover the soldered joint with heat shrink tubing and your set.

RE: 4 stroke engine problems
 

loughbd, on your system did you use the servo with the eccentric or use a switch on your transmitter to operate an on/off switch in the plane?

RE: 4 stroke engine problems
 

Servo wheel cut off like a cam. I'm cheap.

RE: 4 stroke engine problems
 

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You don't need no esteenking onboard glow for normal engine operation. You do need to ensure that your fuel tank centerline is not too high when compared to the spray bar centerline. You also need to drop your membership in the "1/2 turn only low speed adjustment club". <G>

Visit a pattern contest. Note all of the inverted four-stroke engines being used. Ask the pilots if they are using onboard glow heat. They will probably begin laughing as though you told a hilarious joke. Now, after you have discovered that adjusting a four-stroke engine for good inverted running is, indeed, possible, go home and get some practice adjusting your engine. Adjust it until it runs right. Don't be afraid to try different glow plugs, fuel, etc. In the end, the fuel will probably end up being YS 20/20 or something close. The glow plug will end up being an OS Type-F, or a clone of said plug.

There is nothing wrong with the OS FL-70. There is nothing wrong with an airbleed carb. If there was, YS would not have used one on their early YS-91 and Enya still wouldn't be using them on some of their high performance engines.

Although the FL-70 is ringless, I imagine it will take a little running time until the engine stabilizes enough for fine low speed carb adjustments to make much of a difference. You don't take a brand new engine out of the box, pop it onto a model inverted and then expect it to run perfectly immediately. For the low price of our engines, it is a miracle that they run as well as they do.

Try as hard as we might, these days, one must spend some time with their glow engine and their running characteristics in order to run them successfully. These are technical little beasts and they require the owner/operator to familiarize themselves with their running characteristics. If you don't have time to do this with a glow engine, do yourself a favor and go electric. There simply isn't any way of eliminating wrapping your noggin' around one of these fine little creatures in order to extract maximum performance.

RE: 4 stroke engine problems
 

If you'll decise to use an onboard glowstarter,leave away the receiver battery.
We don't use the receiver battery for nothing else but for the servos.
Smoke pumps,onboard glowstarters all use another battery.
I prefer a 2000mah to be sure.
Enjoy.
Kostas
Greece

RE: 4 stroke engine problems
 

Hi;Have seen several of those FLs in use!They require longer break in much more than you would think!Before you get to upset with it maybe ask for reply from owners!Eventually run fine but are a real bear to deal with for first gal.or so of fuel!

RE: 4 stroke engine problems
 

TimC i checked this product on Tower and says that you can only use this on-board glowdriver if you have a PCM tranmitter-receiver.
???????

RE: 4 stroke engine problems
 

Kostas, if you read the tech notes, it is explained:
***For this unit to operate properly with ONLY Futaba PCM***
***and ONLY Hitec RCD receivers, user must get an amplifier from Ram.***
This is a FREE plug and play module with connectors to simplify installation.
***Send the header card from this package and $4.00 to cover postage to Ram.***
***This module is not necessary for any other receivers.***

RE: 4 stroke engine problems
 

But can i use this charger with it http://www2.towerhobbies.com/cgi-bin...?&I=LXHCE6&P=7
It is a tower hobbies nicad wall charger the chargers a 9.6 volt transmitter bettery and a 4.8 volt dc

RE: 4 stroke engine problems
 

Cambo, that charger will not charge a 1.2V battery. Are you using a glow starter off a panel now?

RE: 4 stroke engine problems
 

Oh, the ram battery is a 1.2 V. Is there someother cheap wall charger that tower sells our do i have to buy the 30 dollar one

RE: 4 stroke engine problems
 

Cambo, Tower sells glow starters with chargers for as little as $14.00.

RE: 4 stroke engine problems
 

Yeah,
Exactly what Ed said. Get the fuel tank where it belongs. This seems to be a lost piece of knowledge these days with all the ARFS around. But even ARF airplanes have some big mistakes. On the inverted setup the tank centerline should be slightly below the center of the carb on the FL-70 (where the fuel dumps into the venturi not the location of the Needle Valve as many engines now have remote needles).

Inverted 4 strokes are normally the easiest way to go. They start better that way and don't flood as easily. The valves allow excess fuel to be dumped each revolution. Just get your tank in the right location and quit fooling around with expensive fixes!

Jimnie

RE: 4 stroke engine problems
 

Thanks guys, mabey i should just try to get it running the way it is. In the World Models Groovy 50 3A, which is what the fl is in, the fuel tank is kind of fixed. You can't move it anywhere else than where it is. Last time I looked the centerline looked pretty close to perferct. What do you guys think the stock setting for the airbleed carb is, any tips for tunning it? Imagine starting from scratch and you have no idea where the stock setting is. I am going to give it one last tunning attempt tomorrow.

RE: 4 stroke engine problems
 

Inverted 4 cycles are the most difficult and dangerous to start. The fuel can collect at the bottom of the cyclinder near the plug and cause a hydraulic lock. That is why full sized radials are always pulled through at least 4 times to make sure oil or gas hasn't collected in the inverted cylinders. Suppose the cylinder is flooded as the piston starts into the compression stroke? Both valves are closed and when you hit it with an electric starter, POW one bent connecting rod or busted wrist pin.

When right side up, a flood is easily cleared by turning the engine backwards.

RE: 4 stroke engine problems
 

As Jimnie mentioned, it's a sad fact that some ARF's are designed for an inverted engine and the fuel tank is in the wrong place. There's not much you can do except re-build the whole front end, which cancels out the reason a person buys an ARF in the first place. How bad does the center line of the tank offset the carb spraybar on your plane Cambo? Anyway, a good starting point for the idle adjustment on an air-bleed is to adjust the needle until the air orfice is half way closed by the needle. If it was mine, I'd be tempted to cut a hole in the cowl and flip the engine over.

RE: 4 stroke engine problems
 

Another easier way to solve the inverted engine problem is to use a Perry oscillating pump. It only supplies the amount of fuel the engine needs. It operates on the reaction of the torque caused by the firing of the engine. As the engine oscillates back and forth the pump supplies fuel. I used one on my Goldberg Cub. Had a saito 50 mounted inverted and with the tank mounted high tended to flood at low rpm or just sitting when the tank was full.

RE: 4 stroke engine problems
 

Well, i just looked at the center line, i would gues that the fuel tank is about 1/4 to 1/2 of an inch higher. I never thought of a pump but that seems like it would add alot of weight? Mabey not though. What if i tried to tune the engine while the plane was inverted on a stand, would this help.
Now that it think of it, last time i tried tunning the engine, it would always quit at idle, even if the air bleed whole was wide open.

RE: 4 stroke engine problems
 

Hey, what if i mounted it sideways? Is there a pitts muffler for this engine? Would that help?

RE: 4 stroke engine problems
 

Cambo, the tank is probably close enough. I'd start with the air bleed hole half closed and go from there. The Perry oscillating pump doesn't weigh much at all. It's just a little work to install, and adds another factor in the tuning equation.

RE: 4 stroke engine problems
 

Will a pump or a onboard glow starter work better?

RE: 4 stroke engine problems
 

Where could i get a pump?

RE: 4 stroke engine problems
 

Cambo, I've solved this problem before with a Cline Regulator, but they are kind of expensive. Try fixing it by tuning again.

RE: 4 stroke engine problems
 

If the engine runs better when the plug is being heated that means one thing, the idle is too rich. When the mixture is too rich the plug element gets cooled by the overly juicy mix and the rpm's drop giving you the symptoms you have. That could be because of a badly located fuel tank or any number of things already mentioned but why don't you just try leaning out the idle screw. If it is a true air bleed carb turning the needle counter clockwise will lean it out. Try a quarter turn at a time untill you get it close, then fine tune it. When it is right there should be no difference between having the glow plug hooked up or not.

Good Luck

RE: 4 stroke engine problems
 

Actually the Perry Micro oscillating pump almost never needs any kind of adjustment other than the factory setting. I have 6 of them and have used them on a dozen airplanes. NEVER had to change the factory setting. Used from an OS FS20 up to an OS120 surpass that had a bad pump. All worked fine. I use them whether I have fuel problems or not.

RE: 4 stroke engine problems
 

Yessssssssssssssssssssssssssssssssss! It runs! I was using way to powerful fuel, 30%. The plane will finally not move at idle. I was using that fuel for a high altitude airfield. Well, the plane got moved to a lower altitude.
Just wondering, how do you now if the engine is running to lean. If the engine runs at idle for 1-2 minutes and slowly sputters and quites, is the idle two lean or to rich?

RE: 4 stroke engine problems
 

Locate the tank correctly, and forget about the extra junk. I personally have had 4 planes with inverted 4 strokes, and not 1 problem when set up correctly.:D

RE: 4 stroke engine problems
 

On setting the idle mixture, it could be either way. You will have to do the pinch test and/or move the needle around some to find out.

Enjoy,

Jim