YOADRIAN

i have a tigre 90 on my bigstick. Its a new engine i had put away a long long time ago and slapped it in this aircraft yet fine tuning is a nightmare. A buddy told me to slap a 4 stroke plug in it but still runs badly it starts great and for the first 5 min of flight it burns up the sky yet when it heats up i start to die in power so we land it and back up the needle to run rich and then it starts to sputter. thought being take off rich it heats up then it will lean out in the air. Is my buddy wrong on the plug issue. Any ideas on this engine, thanks for any help

broke_n_bummin

What fuel are you running? Instead of richening the LSN, set the high speed to run just a tad rich. When it heats up, it leans out too much. Also, if it's in a cowl, make sure it has enough ventilation. The only time a 4 stroke plug ever helped me is when the engine was inverted or I was running 15% or more nitro.

spitfireboy

My Feedback: (1)

have you checked your picp-up line in tank? up at the tube you could have cut or punched a hole in it,, also make sure your carb is sealed good at case and not sucking air

j.duncker

My Feedback: (2)

The key words here are NEW ENGINE!

It is likely that it needs more running in. Some STs will take 3 to 4 hours to settle down.

HighPlains

My Feedback: (1)

Low oil fuel can cause this problem, but I also suspect that you are prop'ed with too heavy a load. Lighten up on pitch, diameter or both. This will help break-in and make the needle setting less critical. Also what is the relationship between the tank centerline and spraybar?

YOADRIAN

Thanks guys i will check into all this i will go back to the starting point with the plug and start with the oil level in fuel then go from there. I am using a 12 X7 on it now my chart says 12X8 or 13x6. It does not seem to be sucking air but i will check the fuel lines and connections. It is just way to sensitive on adjustments. I Have 2 tanks break in and about 4 to flights on it. I was having a black sut on the muffler connecter and i tighten the head bolts a tad. I posted this picture to give you and idea what it looks like and the spray bar to centerline view. thanks for your help i will keep you posted.

carlosponti

My Feedback: (1)

first thing to always do with a super tiger is ditch the glow plug it comes with. I have used Fox long with idle bar with all of mine. make sure you have a good tank had a 45 i couldn't get tuned in right till i replaced the tank. what prop did you use to break the engine in?

burgh_guy61

My Feedback: (11)

Another thing, you can remove the carb and look to make sure the opening in the spray bar is at 90 degrees to the opening. They can sometimes be rotated a little and not be right on in a tigre.

jaka

Hi!
You should be using a 14x6 APC or RAM prop! Those are the best plastic props available world wide. Fuel should be 5-10% nitro and glow plug Enya 3 or OS 8. 15% nitro fuel is a waste of money!
12x7 or 13x6 is too small props. And Master air screw and a plastic spinner should always be avoided...that simple!!
Fuel tank should be 12-14oz. Placed in lots of foam so that the center of the tank is in line with the fuel intake orifice in the carb when airplane sits horizontal (tail lifted up).
This is very important!
It´s also good to use a 2 clunk tank system (one for pressure and one to carb) called Uni-Flow . This system gives more even fuel flow to the carb. Better still... use a Tettra "Bubble less " tank. These are the tanks that all pylon racers use.
Hope this helps.
Been flying and racing for 33 years!

Regards!
Jan K
Sweden

YOADRIAN

Guys i can not thank you enough, I will begin by checking everything as you all stated and change plug and prop and i will lose the plastic spinner and go from there. I will post when i get back on sunday and let you all know how it went. Jaka nice DC 3 Thanks again guys talk soon. Almost forgot i broke it in with a wood zinger 12x7 (EDIT) Well guys i just had a look at the aircraft since this is an arf big stik 60 room to play is limited. I slapped a 14 i had and measured the distance to hit ground, it came out to 1 in. I had changed to a duel spring set up on the front landing gear due to the weakness of the stock one and you see i have not to much room to play. The tank sits a bit lower with mount and engine i am 1 inch +/- from the intake to the carb as you see in the pictures. I would really hate to flip the engine over to line it up if it would. And who said this is not fun.

Ed_Moorman

My Feedback: (1)

We have a Super Tigre 90in a Big Stick 60 in my club. The engine runs great.

That being said, it went through 4 owners until it did. No special tricks, it just took about 3 gallons of fuel to break-in. Once they are broken in, they run great, have plenty of power and seem to last a long time, but don't expect to drop it in a plane, make one flight and adjust it like you do an OS. It ain't gonna happen.

Our guy runs a 13-6 on his and it sings.

Jester241

Hey,I have a big stick .60 with that same Super tiger .90 on it,and have about the same size prop (12x6 I think). Sounds like about the exact same setup. I will admit that at first my tuning also seemed extremely crazy. Then after alot of messing and deadsticks,my instructor slipped a piece of fuel tubing over the needle valve to help stop any air leaking about the thread of the needle valve and WHALLA..............My big stick with my super tiger .90 is BY FAR my best running and most reliable plane I got and I dont think I've touched the tuning for almost a year now since the fuel tubing trick(knock on wood). It either worked or it was just coincidence everything decided to work at the time.

So anyway,I highly doubt its your tank setup,prop,or anything like that. And I will agree that the stock glow plug is junk,so get whatever glow you got in it out and stick in an O.S. #8. And make sure your SURE you got the fuel lines going into the tank hooked up right. I've seen several guys spend days trying to tune and engine only to realize their lines where mixed up even though they swore they werent. And yeah....it might take awhile yet to get broke in and it MIGHT help.

YOADRIAN

ok guys or gals, saturday pulled fuel tank, installed new fuel lines, pulled plug installed a os8, removed 12x6 prop installed a 13X6, master type, no apc in that size was available, but it was ordered thru HS. Removed spinner and went to 15% on fuel. Had three guys adjusting it at the field. results after all that, dead sticks, flys slower, loses power in flight and black sludge from exhaust elbo. Things i have not done, ck spray pattern at 90 deg., fuel tubing on needle valve or the fox long with idle bar plug. I Going to pull the engine this week and put it on my stand and go from there. I estimate i have gone thru 1 1/2 gal of fuel on this thing so far. Funny i can build airplanes without issues but tunning is not my forte. The manual says pinch the fuel line and if rpm goes up turn the needle 1/8 turn in (lean). cont this untill the engine does not increase in rpm anymore, then back off 1/8, then it should be set. Then i get a guy at the field who says 5 deg of temp change outside is 1 to 2 clicks in or out depending on outside temp changes going up or down. Then another says run it like a 4 stroke and have it lean out when you point it upward, when you need the power. I Do not buy it, i rather go with that fact that this engine still needs a few more gallons run thru it. So it stays on the stand untill the thing runs right. I WILL not give up on this engine. these are some picks after that day with the black sludge marks after cleaning and fuel line set up.

broke_n_bummin

I wouldn't use 15% till it's broken good ... like close to the 3rd gallon. 10% premium (20% oil) should be enough. ST says that the spraybar needs to point straight down the throat of the carb ( http://www.supertigre.com/faq/product-faq.html#q22 ). Mine still won't run 15% unless I have a H9 4 stroke plug or a fox super plug in it. Even the #8 plugs seem to be too hot. Try a colder plug. I broke my last one in with a 14X6 and has been twisting a 15X4W for the last 4 months almost religiously. The only complaint I have about the Chinese STs is the muffler.

Jester241

....thats what we like to hear! With enough messing with it,you'll get it tuned and running good. And you'll learn alot along the way that will help you on your next tune.

daven

My Feedback: (1)

Is the carb nice and tight against the O-Ring?? I've seen some leak air there.

Loosen up the retaining bolt and press down hard on the carb (into the O-Ring) and tighten up the bolt well. Its very helpful to have a friend help out with this.

Mine runs like a top, right out of the box, been very happy with this motor.

flipstart

Hang in there-the G90 is an awesome engine-but as has been stated it is a bear to break in-put it back on test stand and run it until you are satisfied all is well-check the spray nozzle for correct angle-last G90 I broke in also created some blackish goo mixed with all around the muffler. Kept on the engine on stand until this cleared up and now all is well. I use the pinch test and tachometer to determine if engine is rich/lean. The pinch test also works well to determine if low end is set properly, with line pinched closed at idle, you should get a very small increase in rpm before the engine dies. At this setting you should have good transition if spray bar is set correctly. Both of my G90s run with OS #8 plugs and MAS 13/6 or 7. I run 15% Wildcat but 10% is mo better.
Good Luck.

YOADRIAN

UPDATE: First I want to thank each and every one of you who have posted, each one of you has been a great help and even if i do not call out your nick, i have checked each post and done whats been asked or double check things that had been done. You guys are right 15 is a waste, I will run the 10%, and keep the 13/6 prop (for now). I Pulled the carb and took this picture seems correct on the spray bar location ( Thanks for showing me how to do this guys). Daven i will recheck the tightness when i reinstall the carb. Flip nice to know that black goo will one day vanish lol. Broke, this engine is close to 10 to 15 years old never out of the box do not know if china made it back then. Jaka a buddy of mine told me the fast way to pressure the fuel system is go to a fish pet store and buy a small check valve used for the fish tank air lines installing the flow side toward the tank on the exhaust vent line . cheap and fast lol. I did tighten the head bolts a bit more, they where not that tight. Do they make a baby torque wrench? I will post after i run it a bit more and keep you guys updated.

flipstart

You might have to tweak the spray bar to improve mid range, but what you have now should not be causing the problem you describe. Try diff tank heights on test stand after you get engine adjusted and duplicate on plane. That's why mine ended up on horizontal, best setup relative to tank height.

ronwc

My Feedback: (404)

Get rid of the exhaust extension and run a 14x6 or a 13x7 13x6 APC prop - give some time to break in, land and readjust if need to not run lean -

daven

My Feedback: (1)

Some of us do use torque wrenches for our heads, backplates, mufflers, and glow plugs.

I use one similar to the one here, you can buy them cheaper off the auction site, I got one for about $60 shipped.

http://www.darrolcady.com/Accessorie...ries_tools.htm

Look for one that measures between 5-40 in/oz thats about right for our models. I tighten head bolts at 14 in/oz and plugs at 35 in/oz.

Works well.

broke_n_bummin

Oooooo ... 10 years old ... more than likely it's one of the gooduns made in Itally. I'll trade ya!!