I noticed both of my engines are a bit sensitive to tuning, and some do respond to a full turn...any suggestions? or tricks?

The only one that I have found to work is replace it with a Perry Carburetor. I fought with my .51 for full season before breaking down and replacing it with a Perry. Wow what a difference it is a sweet runner now.

The super Tiger carb is probably one of the best carbs in existence today.

any substitution with another brand carb wound be a down grade.

Look here - http://www.rcuniverse.com/forum/forumid_163/tt.htm

There is a ton of great ST tuning info.

Jack

the hole in the spray bar MUST point straight down the venturi. Anything else and your in for more headache than you can imagine.
The only engines I buy these days are ST because of the value, the power and yes the ease and reliability of use.
Before putting another carb on there, and forever saying 'the only way to make it run...' make sure the spray bar is in there correctly. it must point straight down the throat of the carb. it sounds silly but it really is very sensitive in that area, but once you get it dialed in you'll love it.

The voice of experience

Follow this rule and there will be no problems

I also have found on mine (.40; .45 and .51), that they like to be run before dialing the Idle NV, they come set from factory with a reach low end, and that's great while it's in its breake in process, after several tanks, the idle needle valve can be reset and the engine will gain some power (great) and the transition from low to high will be smooth.
I also have found that they are great engines, I like them a lot. The only issue that I could find against them is related with weight (never performance).

Like posted before, make sure the hole in the spraybar is pointed directly into the throat of the carb. Another one that people in a hurry can miss, the supertigre carbs fit tight, be sure that it is seated very well against the o-ring under it, push down hard with your thumb then tighten the screw. Also as posted above, after checking these things out run a couple of tanks through it. The .61 and the .45 I have are convincing me more and more every time I fly with 'em that these engines really are the best for less.

One more thing, both of mine burned out the glow plug not to long after I considered the engine broke in. I run at least a gallon through them before I really tweak the tuning. Maybe it is all of the rich running I do not know. After the fact I run a standard old fox long plug in them now. They are still going strong, the .61 has several all day flying sessions on it.

I've had serveral Supertigres .60s and .75's, where no matter what I did, the engine would either:

- Transition GREAT but idle very rich.
- Idle GREAT but transition poorly.

And no matter what there was no good in between.

I saw an article about an Avastar ( sp? ) on Sports Flyer Magazine, where the author modified the throttle barrel slightly to cure a similiar complaint.

I did this with my problematic SuperTigres and this cured the problem.

The fix allowed a richer LS needle setting, while letting the engine idle a bit more lean... but curing the transition at the same time.

The fix involved cutting a small half moon shape into the throttle barrel intake body, at the point of maximum closure.

I've done it on three engines thus far which cured their problems.

Strangely I've also had other ST engines that were just fine without the modification.