Hi guys, I have a ST 40 and a ST 75. I hate the big silent muffler they put on these. My question is will the Mac's muffler help the engine. I've herd a lot about the ST carbs and mufflers being crap. what do you think?

check Tower Hobbies they show them both in stock. I have used them on OS 25 & 46 and have found little difference in performance over stock muffler. I also have 1 on a YS45 and I am disappointed in its performance.

You won't regret putting one on your Super Tigre. Even if performance gain is minimal, you won't have the problems that come along with the stock ST muffler.

I haven't had problems either with the Stock ST mufflers or the MAC's mufflers.

No performance gains with the MACs, though they look nice.


But yeah the stock muffler is YUGLY!


As far as the ST carb, I have a .75 engine where the carb itself leaks air around the intake barrel.

This causes my engine to continue to run with the throttle FULLY closed until I pinch off the fuel flow.

While the engine runs reliably, it's very annoying that this is the case... and there is no leak at the carb to engine junction.

I've verified that the air leaks around the throttle barrel itself... ugh.

A new replacement ST carb does exactly the same thing.