Hey everybody,
I'm having a 3W50i but having trouble finetuning the engine. I'm practically new to gas-engines and would like to have some input about how to adjust my carburator. How can I now if the engine is to lean or to fat ? How little (or much) do I have to turn the needles? What do I have to tune first, the upper or lower needle? Some tips about proper starting would be helpful to. I have a tuned pipe and am using a Menz prop (24x8) on a Cap 232 with +/-82 inch wingspan.

Any reply is helpful.

You can start with both needles at 1 1/2 turns out. The LO speed adjustment should be such that when you throttle up the engine there is a smooth transition to full throttle. If it bogs down it is either too lean or rich. At 1 1/2 turns you can turn the needle in 1/8 turn at at time to get the correct (smooth) transition. The HI Speed needle: after a smooth transition to hi speed the engine should run smoothly and not hot. If you continue to turn in the HI speed needle the engine will (at some point) become lean and begin to loose power. In that case (should it happen) turn out the HI speed needle untill the engine is running strong again and then turn it out about 1/8 turn more, for safety. Hope that helps.

If you 3w50 is the new model with the new ignitions the ajustment of the needle is

H=1 turn out
L=1.1/4 out

You have to wait that the engine take temperature for the adjustment, run the engine for 3 0r 4 minutes then make the adjust.When the engine is cold have a little lag in the transition from mid to high like lean this is normal

you can check in this link http://www.3w-modellmotoren.com/engl...toren_com.html in the seccion of engines basics settings.

Oscar Silfa

By other way if you not have the proper length in you exhaust manifold you have problem in the adjustment of the carburetor
The length of the manifold have to be between 170mm & 200mm measure from exhaust cylinder

Oscar Silfa