pc55bomber

Hi
I disagree completely.

I can't believe the number of posts I see that claim ST carbs are bad.
Most of the "BAD" ones are simply not set up correctly, I have not seen a bad one yet!
I have seen a lot of guys who continually have engine outs and its down to poor engine setup.
IMHO these are the easiest carby to set up.

You have to run the engine in properly, especially the ringed ones.
Then set the bottom end and it should be sweet as.

See my post no.282 to set up your carby the Italian way.

I'm no expert but its worked for me for years, never had any problems with my Tigre's, ever.


Cheers
Paul

buzzingb

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Yea but after 3 or 4 gallons you begin to wonder.

speedster 1919

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XJET The dirty little secret is that ST90 was probably just afew clicks off or 1/8 turn off on low speed needle. The other secret is a Tigre will run lean when other engines won't. All ST's are set way rich both high and low needles out of the box new ,unless someone has fiddled with the needles when looking to buy one.

buzzingb

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Adjusting Needles/Noone Know It All

Yesterday I spent about an hour surfing the net looking at evey way possible to adjust/tune the needle valves. I now are inclined to believe that there is no one way to do it and noone knows everything there is to know about it so don't convince yourself that you are some kind of tuning guru. Basically there are a few different way and I will try to list them here but that doesn't mean that is all.

1. Pinch and listen for rpm increase or decrease. (Rpm increase=rich Rpm decrease=lean)
2. Tachometer-use the tach to get peak rpm back or 300-500rpms (seem to be most accurate)
3. Temperature Gun- used primarly for cars but can be used for planes.
4. Ear- twist needle and sisten to sound of engine (sees to be most inaccurate).
5. Fly-it- get the needles close, just a little rich and fly it, leaning each time you go out to the field until it is at optimum setting. ( may be best for breaking in engines)

If you have another way please post here and I will add it.
To sum it up I believe we should use all these ways and hould hold plane vertical to see it there is an rpm change in vertical position and should check with tank half full.

JuanPu

From what I've heard to our engine guru, ST carbs need a thorough process of sealing all the possible (and undesired) air entries, prior to starting it for the first time.

BTW, someone has told above STs are much more expensive in Europe... That's true, so most knowledgeable people buy them abroad through the net. I have just bough a ST 51 from Tower Hobbies that including shipping costs and SuperSaver discounts has costed me 58 €, that is pretty good.

buzzingb

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With all the Super Tigers I own now I have never had a problem with air leaking but I do realize it could be possible with any engine. I learned about the air leak on two cycle engine years ago with a 250 Honda that kept quitting with me miles from civilization due to sucking air aruond crank seal. RTV Silicon works well with that for our purposes.

buzzingb

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One way to set the needle is to just fly it and watch for vapor trail or hesitation. The last few engines I broke-in and flew I resorted to this method. I intentially started too rich on both needles as to break-in in the air and it works well if you don't have dead sticks. My latest as Super Tiger 90 only had a half tank ran through it when I loaded it up and headed to the field. It did gurgle a little an transition the first flight then when I landed I leaned the needle two clicks and it put it to running much better but still too rich. I flew it for about 5 tanks that day and haven't had her back our but when we do get out again I will observe the vapor trail, transition, and temp of engine and will evaluate is I need to go another click or two leaner. Why adjust and break in a ringed engine this way you may ask when most burn tank after tank on a test bench? Well I have a good open area where I fly so I can land if need be at any time. It also doesn't hurt the engine as it keeps it cool and I never run full throttle except for occasional burst and back to half throttle. It gets use to doing what is is going to be doing and the up and down throttling should set ever surface fine. Now I don't recomend this to you but for me I think it is fine as I am having fun while running in the engine. Lets face it the bench is the bench and doesn't replicate the conditions found on an airplane flying around the sky.

buzzingb

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What Does The Needle Valve Effect?

Well I will say now that I am not qualified to answer this as I have only a vague understanding of this. Fuel mixtue in two cylce methanol/nitromethane buring engine is critical as it is in other engines. It is kind of like the blood in the human body. It helps provide proper timing for the ignition of the fuel/air to provide combustion. If it doesn't happen at the proper time it could put undue strain and heat on the engine. If you have ever seen the top of a piston that was burnt or pitted due to preignition you know what I am talking about. It provides the proper fule/air mixture that helps cool vital engine parts. Methanol cools much of the engine as it is drawn in and circulated around the engine. It provides oil for lubrication and heat absorption and removal. Needle valve mixtures are the root of most problems encountered in glow engine operations today. Many people have tanks positioned above or below the carb that will make adjusting the needle valve properly impossible, I will say it againg if you tank is positioned above or below the centerline of carb adjusting the needle valve properly is impossible. Yes it is true you sometimes can adjust it so the engine will run but now properly even with regulators and check valves. I know I have only touched the surface of this topic so if please let me know what I have left out.

buzzingb

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Is There Times When I Need to Adjust the Needl Valve More ??

Yes I believe there are time when you need to adjust the needles. When you are breaking in a new engine you always want to start out rich and lean it up gradgually and this is for on the test stand or in the air breakins. Another time is when you change fuel or add more oil as this can change ingnition timing as well as fuel/air. Weather, this is less critical but it can have an effect. After the needle is set properly and everything has been running well with cear signs of vapor trail then if a needle adjustment seems necessary then you might suspect other causes first like glow plug, tank, fuel blockage, etc. This has tricked me just recently with a fuel blockage in the needle valve area. I believe it was dried castor because I was only flying the plane ever month or two. I began to adjust the needles valve instead or looking for the real cause of the problem. MISTAKE!! I shouldn't have done that. What I should have done as look first to see what had changed after installing a new glow plug.

buzzingb

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Engine Related

Remembe, that even though the airplane and engine never appears to change, there are changes occuring all the time and the forces the plane and engine itself exhert will cause change. Fuel tanks can shift, age, deteriate, and holes come in lines. Fuel can go bad. Glow plugs go bad. Bearing wear out. O-rings wear out. and the list goes on and on. The point is check all the possibilities before you create another problem by screwing on those needle valves because it is mighty tempting to give it a slight screw because it is easy to get to and the whole time you are tinking it is the root of the problem. Just recently I read that about a man blaming his glow plugs because when he took off the glow ignitor it would run properly or idle. This may not be glow plug related as it very much sounds like a neelde valve related problem but it could evern be related to something else.

buzzingb

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Can Glow Plugs Make Up For Improperly Adjusted Needle Valves?

Yes indeed a glow plug can help compensate for needle valves being improperly adjusted. In fact if you change glow plugs (form one heat range to another) you should readjust the needle. A rich needle setting may be slow to ignite so a glow plug migh help get it back in time or vise versa a lean setting may be compensated for by another type of glow plug. That is why it is impostant to decide what kind of fuel, glow plug, and etc that you are going to use and try to stick with it. A change here requires a couple of changes there and etc. Many believe in the one glow plug or another. I have been told that if I would change glow plugs on my 2300 that all my worries would be over. Well I thought why not give it a try as it would be cheaper to try this than to correct the real problem so I did and personlly I didn't notice one bit of difference. I tried OS 3,5,8, F another man said well try the Fox and another said try this or that. I couldn't tell one bit of difference with any of them so finally I just installed a Tower Plug and it is still in there to this day and works just as well as the others only better now that I have changed carbs. Yes is is fun to experiment as long as you have plenty of money and time and who knows you might compensate for the needle valve being out of adjustment also.

buzzingb

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Just recently I noticed that the Tower Hobbies Company was offering a new type of glow plug, don't remember the name just now will report back about that latter. Probally just another plow to get our money. Lets face it $2 -$8 for such a simple little thing is redicioulus. It's probally only cost a few pennies to make on of these things so if you can get just a few people to say try it as it will solve all your transition problems, you could be a millionare.

NM2K

My Feedback: (14)

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Three or four gallons of fuel at mostly half throttle accomplishes nothing. The engine will not break-in/seat properly until ran for a prolonged period at high throttle with a somewhat rich mixture. This "prolonged period" can be broken into smaller running sessions. The total time is what matters. Thermal cycling does help the situation, or at least it can't hurt it.

Saito's instructions for break-in are not applicable to Super Tigre two-strokes.


Ed Cregger

buzzingb

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That is one reason I like to just go ahead and put one in the air and let her do the job it was intended to do. I really don't like wasting fuel on the ground plus the engine is running at its normal operating temperature and prop load. Year if you have a plane that is prone to falling out of the sky like a brick if the engine goes dead then don't pay all this any attention and get the ole test stand out. I don't mess with that kind of plane too much but if I do I try to breakin the engine intended for it on another easirer to fly plane. It doesn't take as long to get the ring seated and everything wear fitted flying in the air to me. This is just my observations. After I have flown about two tanks of fuel I normally open her up and lean her down some but now all the way. This is a gradual and suttle way to get everything going and fit properly. The engines really respond well to this type of breakin and man is it fun having that thing in the air. After a couple of time out at the field ( maybe a gallon of fuel through her) I tend to go up in prop size and then it is all over and the real fun begins.

progolfer100

My Feedback: (23)

I am having trouble getting a new ST 61 to run properly.. Heck I am even having trouble getting it to run at all. Can someone give me a starting point for the low and high settings? Thanks

w8ye

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Here's the owner's manual

http://manuals.hobbico.com/sup/sup-manual-v1_1.pdf

buzzingb

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Make sure you open the idle needle open enough to alow fuel flow (proper fuel flow) for the high needle (maybe about 1/2 across the cat eye or jet, in spray bar if you look at it from the bottom of carb). If you don't want to take off carb just screw it out several turns and take a small piece of fuel tube and check and see if you can blow through it at idle setting. Set the high needle to peak and back off 500rpms. Then set the low needle by turning in 1/8 inch increments till it starts to idle and transition without hesitation. Now if you have other problems there is no need to go through this process until you have corrected the other problem. Since you say run at all, that indicates to me that you may have other problems that you aren't aware of.

buzzingb

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Before you start twisting the needles take the engine off the plane and plance on test stand. Put in a new glow plug, get some fresh 15% fuel with 18% oil that contains some castor and then open the low needle a few turns and fire up and set high needle to peak and back off 500. The start setting low needle as already advised 1/8 turn at a time untill you reach good transition.

buzzingb

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If this doesn't work start looking for someone in your area that is an engine guru. The 61 will run well because I have on but if there is a problem somewhere it can be very puzzling to figure out and sometimes other can spot the problem right off.

buzzingb

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Displaying Engine

Man I feel better I now have my spare Super Tiger 51 sitting an a glassed end table beside the couch. Now all I have to do is look ove there and start dreaming us a way I will put that engine to work. I made a wooden display stand out of Hondurous Mahogany. I use a band saw to rough it out and just clampef my portable belt sander to a table and sanded the rest to shape. Guess what kind of oil I finished it off with? Yup, Castor and it looks great. Almost any kind of oil will bring out the luster of wood. I learned this in high school wood shop when my teacher instructed me to bring in some cooking oil to finish a mahogany bowl I made the wood lathe. I sure wish I could put my pictures on the computer but it just doesn't have enough memory, too old and slow. I plan on upgrading in a few years and then I will share some of the great things going on in North MS. I have had the engine in there for a day and my wife hasn't even spotted it yet, now I am wondeing how long it will take her to notice it.

buzzingb

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Castor Oil

It may be the only thing we use that isn't harmful to us or the environment. That castor bean and castor oil has been used for many purposes and still is. Funny thing is the castor bean itself could be toxic (ricin) so don't ingest more than 7 beans or it may be over. It makes a great lamp oil with a bright light. Great skin lotion, I found this out with glow fuel. It is acidic. I am amazed at this after reading about this small bean but I must say I have never taken any as a laxative. Helps women during child birth. There are so many uses for this stuff that I won't even attempt to list them but if you are interested just vist the library and check it out.

Another thing is that if you ingest enough oil it can kill you too but I takes a good bit. At one time it was used as torture.

buzzingb

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One funny thing that catch my attention is that the article said that castor oil doesn't dry up very easily and is stable. I seem that many have had problems with it diying in the glow area. HUM don't know about that??? HUM

NM2K

My Feedback: (14)

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All of that sounds good to me, Bob.

The first couple of tanks on the bench are the critical ones. Once the engine is throttling fairly well, further bench runs are okay, but not necessary.


Ed Cregger

Not24

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About break-in

When I first ran my 2300, I was really impressed with it. It ran smooth and quiet, throttled and idled well after about 32 ozs. of fuel on the test stand. I ran several more tanks through it before mounting it to the plane, and I thought it was ready to fly.

The first thing I learned was that the fuel draw was insufficient in flight, and the engine would die at half throttle in level flight. This is after playing with the muffler to get the pressure up. That was the beginning of my thread about testing and experimenting with that engine. It was originally called "my 2300 only likes one prop".

As you guys know, I have had no troubles with the engine after learning what the engine needed to run right. Basically, they are; prop for 9000 rpm, 15% nitro, and a carb with a smaller intake. The addition of a fuel pump made it even better, but wasn't absolutely necessary to get it to run.

I tried to finish the break-in in flight, but with my engine, it was not possible. I have since run several gallons of 15% through it, and I know it's good and broken-in. It pulls my 11# Sukhoi very nicely. I think it's just as strong as a Saito 1.80, based on prop/rpm figures I have seen. I would highly recommend the 2300 as a large sport plane engine, warbird, or IMAC type airplane engine. Nothing against ST, but the 4 strokes are much better for 3D flying.

I have a new G90 for a Midwest Citabria that I think will do very well. I have another plane to use to get that engine broken-in.

Hobbsy

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http://www.supertigre.com/faq/product-faq.html#q22

You'll find the answer to virtually all ST questions regardless of size.