I've owned three Tower 46's from when the first came out as well as worked on and adjust many other's Tower engines.

I also owned a GMS 61 for a few years. Though I never had any trouble with the 61, some of the Tower/GMS engines that belonged to others were a hand ful to finally get to run correctly

I've worked on a Tower 75 for the last three years whenever it had a problem including the carb. Every time I go flying, it is the only engine the other guy has.

I've put bearings in two Chinese ST 40's and one Chinese 61

I've owned 12 different Italian ST engines and some of them I worked on extensively in the past 40 years and worked on many other people's ST engines in the last 45 years.

The design of the genuine Chinese ST carb spray bar inside the venture is no different from the GMS/Tower design when you closely look at it.

The GMS spray bar is pressed into the carb body whereas the super tiger spray bar has a flange whereby it is held into the carb body with two clamp screws from outside the high speed side of the carb body. The ST HS needle is threaded directly into the spray bar assembly instead of the carb body or being a separate assembly mounted on the rear of the engine..

When the Chinese started making the carb parts they changed the design of the fuel metering part of the spray bar from the way the Italian ones were made. This was some 5 years ago. I cannot say the redesign was bad for the All Chinese ST engines I've experienced run very well even in midrange.

I have had no trouble getting either the GMS, Tower, or any of the ST engines running well. The design of the ST carb (Italian or Chinese) works as well as most any two stroke glow carb.

You can go ahead and condemn whatever brand you like. I'm well experienced and have no trouble with them.

My point is that if you remove a current production Tower 75 carb and a current Super Tiger 75 carb and look in them from the engine side, the spray bars look identical up in the venturi. What you will see is that the LS screw goes inside the spray bar and there is a notch milled across the spray bar where you will see the end of the LS screw half way across the notch when the throttle is wide open. Yet the carbs are made rather different elsewhere.

My Tower 46's had a spray bar more like an OS engine that was completely different from a Super Tiger