As far as I know, all of the single cylinders have the exhaust on the right side, looking from the back of the engine. I currently have a .45FA , a .72 FA and a 115 FA. All in use. Additionally I have had another .45, a .65, a ..80, A FA and GK .91, a 1.20 and a 1.80 all singles and an older 270 twin with the single carb. All started easy either upright or inverted ( did not try the twin inverted, anyway, is there an "inverted" for an opposed rwin?). The 270 twin swung a 20 x 10 wood prop at about 6300 RPM compared to the st3000's 6900 RPM with same prop. I have also had YS and OS 4 strokes but the Saito was most friendly. I also use regular 15/15 glow fuel. DGM