I have a super tiger 2300 and a tower hobbies .75 that are both giving me the same problem, if I pull the throttle back fast after running at full throttle the engine quits. If I pull back on the throttle slowly the engines dont seem to have the problem. I have the idle and forward transition tuned in but cant figure out the full throttle to idle transition. I set both engines so that on idle to full throttle transition their is a very slight hesitation from being slightly rich.

P.S. the tower is running a bisson pitts muffler.

....almost any engine will die like that when the throttle is chopped from full running to
idle. I learned to give back two clicks (on the stick) of throttle when I chop the throttle
for any reason....not just landing. This will prevent the engine from dying out and perhaps
resulting in damage to the plane if bad things happen trying to land too far from the field, or
in a bad position. I never chop the throttle all the way until the plane is right over the threshold
(desired landing spot) and just a couple feet off the ground.

This technique also prevents stalling the plane on final approach to landing, especially if there
is a headwind. Lots of times the plane is damaged from not making it back to the field, to
the landing area.

FBD.

Sounds like your running them a little lean on the low end.

It sometimes happens on well tuned engines like Dave said.

And don't go around "chopping the throttle". It's so beginner.
You often see people in the pits demonstrating one thing or another by banging the throttle forward as fast as possible, then chopping it.
All that achieves is to raise the eyebrows of seasoned flyers and raise the question "what are you trying to achieve?"
Throttles should be ROLLED forward and backwards. Not banged forward then chopped.
Nothing, absolutely nothing disinguises a beginner aerobatic pilot (even though he may have been flying for several years) better than listening to his throttle technique.
Bang and chop, an on off throttle. Total amature.
Roll it... slowly.
One and two and...

wow...if I have the engine tuned right I expect it to do what I want. Without funky throttle stuff. If it dosen't I look for another problem.

"It's so beginner" isn't helpful.

I've seen where there is a time and place for both kinds of throttle management.

A Lomcevak would be hard to enter by bringing up the throttle slowly. Conversely, chopping the throttle quickly on final isn't such a good thing most of the time. Stall turns work well by using a technique somewhere in the middle....at least for me it does.

What I'm trying to do is get the engines set up so that they will take anything on the ground so there is low chance of dead stick in the air.