I'm sure he means 25 to 1.

If your engine is new then you got the new muffler which is a drag on power. 3mm changed the muffler design a few months ago and put on a smaller outlet pipe which drags power down at least 400 rpm.

Since then I only sell the engine to people who plan to use a canister or who understand and accept the reduced power with the stock muffler. I'll resume promoting them when 3MM goes back to the original design.

You want a muffler with minimum 7/8" OD outlet.

TF