One possibility is that you're just not getting enough fuel, either at the high- or low-end. I've never had the 1.35 but have had the 1.8 and 2.10. I imagine the 1.35 is the same regarding the low-speed adjustment wheel. The "+" on the low-speed adjustment wheel does not mean more rich as you might expect. It is actually degrees of leanness . . . Moving it to the "+" side means you are leaning it out, not richening it. As taken from the 2.10 manual - "You may turn the "idle knob" clockwise to lean or counterclockwise to richen the idle mixture. Do not turn this adjustment more than about 15 degrees in either direction or you will cut off the fuel supply to the engine." You might want to try setting the low-speed wheel to the center, or neutral position, and get your high-speed adjustment set first as suggested in the previous post. Start out with about 3 1/2 turns on the needle valve. Once you get it running at WOT lean it out until you get peak RPM and then richen it so that your RPMs drop 200 - 300. When doing this, if you have a large tank such as a 24 oz., do it without much fuel in the tank unless you're running a pump or regulator. Reason being that the weight of a full tank of fuel will help "push" the fuel and as you burn it off the motor will lean somewhat because you don't have the weight of the addititional fuel. Once you get that set, let the engine idle for about five minutes. Quickly advance it to full throttle and see what happens (with the low-speed wheel still set in the neutral position). If it sputters and really smokes, lean it just a tad. If it dies, richen it. You have it close when you can idle for about five minutes and hit it to WOT with a smooth transition. Just be sure to just barely move that wheel when adjusting the low-end. Hope this helps.

Dan