RickShane

My Feedback: (1)

Iam breaking in my ST G90 with pitts muffler.Irun it at half throttle VERYrich, lean it out and let it get too hot to touch then richen it up and cool it back down and repeat.After 3 tanks ofheating it up and coolingit down Istarted tunningit andblew my header gasket. Replaced itwith a flat sheet of autogasket Iuse on all my Super Tigers....A lot better than ST gaskets! Does anybody need to set their low speedneedle? (They sayit comes pre setfrom the factory, Idon't think so!)Ilive in Utah at4600 feet above sea level,and Ialways have to turnmy low speed needle in about one turn because the air is so thin up here.

wcmorrison

My Feedback: (2)

Rick, I would do a search on break in procedures.  MECOA (that would be www.mecoa.com) has a nice blurb on breaking in engines.  I would follow the instructions that Super Tigre gives you.  Running real rich on a ABC/ABN engine is a No-No, they are best broken in in the air running rich enough to ensure they don't go lean.  Ringed engines do like to be run rich, ala 4 stroking.  That is, the engine is running so rich that they sort of burbles along.

My advice is that new engines should be run with some Castor oil in the lube mix.  Great stuff for protecting engines against lean runs.  I use it all the time in both two and four stroke engines.  Also 20% total lube to start with.  After they are broken in, then you can get away with a lot less lube (not recommended for longevity of the engine).

Its your engine, you can do what you want with it.

Chip

Konrad

There is NO such thing as factory pre set! There is a factory setting. And this is just to help you get the engine to run.

The factory has no idea of your atmospheric conditions, fuel tank level, fuel type or prop. The adjustment it there for you to adjust. Otherwise they could save a lot of money by just making the mixture feature of the carb fixed (nonadjustable).

So spin the needles to get what you need. You aren't likely to break anything.

All the best,

Konrad

Konrad

Avoid the temptation to go with higher nitro fuel for your altitude. At your altitude while the air is thinner and the cylinder pressure is lower than at see level and the engine can benefit from higher cylinder pressure. The air is also less capable of taking away the heat (there is less air). So if you feel you need more power from the 15cc Super Tiger, you can change the head volume to up the compression. Higher compression gives more power and at a higher efficiency so the load put on the cooling system is not as great as the power increase.

This thought process worked very well for me when I flew at 5K to 6K feet altitude.

Get rid of that manifold/header gasket! It will only cause you pain and help the importer with their muffler sales!

I can't think of any reason to run less than 100% castor. It helps cooling at high altitude and keeps the bearings from rusting. Other than clean up I don't know of any benefit to synthetic oils for your engine.

All the best,

Konrad

rcdude7

My Feedback: (264)

The G-90 is a ringed engine and you should run it in at full throttle very rich. When the engine will run reliably on the bench, you can begin to fly it, set rich of couse. I have good luck getting my break in time in the air where the engine will run cooler at a leaner setting instead of excessive bench running. I have had better luck not using a exhaust gasket at all, just ues a thin seal of hi-temp orange RTV silicone and you are good to go. The gasket will compress and allow the muffler to move, causing it to loosen eventually.

Hobbsy

My Feedback: (102)

Yes sir, Dude is right on, its real simple with SuperTigres and their exhaust gasket, either lose the gasket or you'll lose the muffler and tear the threads up in the process.

jeffie8696

Have to agree with Konrad (thats a first) . The "Factory Setting" on most carbs is a joke. I have seen very few engines that Icouldnt get to start at 2 turns open then adjust from there.
Just the other day had a newbie at the club trying to eliminate a rich midrange with the high speed needle. He had a rich low speed needle causing it to load up and had leaned out the high speed needle to an unsafe (unhealty) lean setting. He is a happy camper now.

RickShane

My Feedback: (1)

This is my 3rd ST and my 2nd G90 ringed. I have become a little expert with these engines. After Ibroke it in, Inow have it tuned and running GREAT with a VERYlow idle. Ihad to turn my low speed in 2 turns. Irun 15% nitro with 20% oil. They love the nitro.

As far as the gasket goes. Like I said the ST gaskets are garbage. Iwent to the auto parts store and bought a square flat grey gasket about 1/16 thick and I cut one out if I ever need one. Ihave been going many years on one plane, on the other Ihad to replace the gasket after about 15 years of flying. But that's on the standard muffler. If Ihave gasket problems with the pitts on the 90 I'll go with the orange stuff. But so far so good.

w8ye

My Feedback: (16)

It will take a couple gallons to get that G90 loosened up to where it could be considered truly broken in. Best thing to do is get it in the air and do the rest while you enjoy flying.

Gizmo-RCU

My Feedback: (27)

My 90 took a while, about 2 gallons to become a really reliable and fun engine. Lots of power, reliable idle and easy to start. What more can you expect? It's a keeper even though it's not being used at this time.[:@]

Bax

My Feedback: (11)

With any model engine, you NEVER, EVER break it in at a part-throttle setting. Ringed engines should be run at full throttle with a very-rich needle setting and gradually leaned over the first 45-60 minutes. ABC-type engines should be run at full throttle and run at the point where it's rich, but just leaned past the point where it has the 4-cycle/2-cycle break. Non-ringed engines with the iron alloy pistons and steel liners should be run as rich as you can get them and still keep them running, and then gradually leaned as they will accept the needle.

If you think that an engine is too hot when it's painful to touch......well, it's absolutely normal for them to become too hot to touch. "Heat cycling" involved running a ringed engine for 2-3 minutes at full throttle and rich, and then shutting them down and allowing them to cool below the point where it's uncomfortable to touch. You then repeat the process. After a few short runs, you lengthen the run times and lean the needle a bit.

In all cases, if the engine will run "all day" at full throttle when leaned just rich of peak RPM, then it's ready for anything. You can then retard the throttle and adjust the needle.

Our experience has shown that part-throttle running for an extended time really won't do the engine any good. Usually, a shortened engine life can be expected. We've seen this a lot with RC car and heli guys who idle the engine for a few tanks as their breakin procedure, and then lean out and go. Those engines won't last but a few gallons' worth of fuel....and then who do you think gets blamed for the damaged engine?

Fuels with a significant amount of castor oil in the mix are better for breakin (and general use) than all-synthetic fuels.

RickShane

My Feedback: (1)

Iran it through a few heat cycles and taxied the plane around,and on the 3rd tank Idid the very rich full throttle thing then leaned it out 1/8 of a turn, waited a minute and leaned it out 1/8 of a turn, wait a minute, and so on. Ihave it running great! I love the Super Tigers!

rcdude7

My Feedback: (264)

But, you still have much to learn, young grasshopper.....................

rcdude7

My Feedback: (264)

If it will run well enough to not quit, it is best (for the engine) to get it in the air and fly. Taxi testing will ony ensure the engine ingests dirt and dust, not good.

Hobbsy

My Feedback: (102)

(They say it comes pre set from the factory, I don't think so!)

Rick, that quote above is something you should store in your "little Expert" mind forever, "they Says" are at the very least 99% wrong. "I knows" can be only trusted so far and then only when backed up by a few facts.

RickShane

My Feedback: (1)

Am Ibeing raked over the coals here?When Isaid Iwas a"little expert" with the Super Tigers, Ididn't mean Iknew all there is to knowabout them, and I know Ialways learn something new with them.However I'm not an idiot, and I DOknow how to make them run well.

Hobbsy, Here's your facts...Ihave a ST51 that I fly all the time eversince 1991. That 51 has at lease over 400 flights on it. My older G 90 Igot back in 1993 and that has aboout 300 flights on it. It's justbeen a long time since I've had a new ST motor. Thus this post. Notice the title of it...How do YOU break in YOUR Super Tiger?

I know how to break them in, and know how to tune them well. I've come across a lot of people on the flying field that were having problems with their ST. I've always been able to get their ST running well.Ijust needed a little refresher on breaking them in. Say what you will, but the Super Tigers I haveare almost20 years old and still going strong. Oh and they all start withone flip or two. I've never owned an electric starter because I don't need it.

Okay now a question...After flying for like 10 minutes and I throttle all the way down the engine is at a high idle for a bit, then comes down to a normal idle on it's own. Why does it do that? Can anyone answer that one?

Thanks for all the input.

ianwynne

Hello RickShane:

>After flying for like 10 minutes and I throttle all the way down the engine is at a high idle for a bit, then comes down to a normal idle on it's own.

My G90 goes to a high idle for 4 seconds, then settles down to a normal idle. I've always assumed it was the flywheel effect from the 13.5 inche Bolly prop which is quite heavy.

I will be interested to see what other people have to say.

Bye, Ian

jeffie8696

Almost sounds like a vaccum leak. Erratic idle is a sign.
Imust admit the Super Tigre I repaired for my buddy ran really sweet once the head quit leaking. He owned it for 17 years or something like that and never got it to run right. Imanaged to get it to idle and transition really really well, Iwas impressed.

w8ye

My Feedback: (16)

After the idle settles down, how does the engine accelerate when you give it the throttle?

jaka

Hi!
If set up correctly all engines should instanly reply to a new throttle setting! Simple as that! It has nothing to do with what prop size you use !
Probably you run your engine a little too lean on the idle setting...or wrong fuel! Do not use more than 5% nitro!!!

RickShane

My Feedback: (1)

It has NOproblem when I throttle back up. It does it on all 3 of my Super Tigers and has done so through all types of fuel for the last 20 years. It don't matter what prop you have on it, it's not a vacume leak, They all run really good, start with one flip, and so on. I run 15% nitro because I live in Utah where we are 4600 feet above sea level. A lot less air up here. Maybe that's it? Idunno. It has never been a problem, or bothered me. When it's hotIt just takes a secone or two to settle down to a normal idle.

Konrad

In sport applications (expansion mufflers) I had attributed this behavior to an air leak. Such as the by design low pressure front bearing anti oiling port across the front crankshaft seal. In high performance piped application I have seen the pipe over ride the throttle.

All the best,

Konrad

jeffie8696

Ihave seen some engines when over propped want to stumble on acceleration(like having your car in too high a gear) but it didnt hurt the idle.