Have anyone had any trouble adjusting the mixture on an 46FX-H engine? I have read that there is a design problem with the carb on this engine, any comments?

Thanks.

Yes, the stock carb causes the mixture to go lean at midrange. This was on the 1st version of the carb, the latest manufactured carbs have a modified spraybar that is supposed to help the mixture problems. The 1st version carb can be modified by drilling an air bleed hole in the carb face in the appropriate spot, then opening up the low-end mixture screw. This helps the mixture to be richer at midrange.

I bought mine just two months ago, how do I know if it has the modified carb?

My engine runs very reach on the low end (otherwise it runs lean at middle), but after it warms up it runs better, is this the same problem that you are talking about?

Thanks.

Does your carb have a #2 stamped into the body? This isn't 100% but that #2 means it has the newer cats eye mod done on the spraybar to richen up the midrange.

Scott

There is a good number of them here....all on 600mm helis and all run great. Match them to the proper muffler, blade size and gearing and they are great. I have a couple that are very high time 20 and 26 gallons of fuel through each respectively.

They do not like too restrictive an exhaust system (I use the Century CN3033A on mine), nore too light a disc loading (loves 600mm blades) or the wrong gear ratio (9:1 or so is great) or any combination there of. A lot of their bad reputation was due to the fact that many where powering up their 30 size Raptors with 550mm blades and the wrong ratios by just popping in the 46. We learned years ago that this does not work. Ditto for the Concept 46 and Ergo 46 that used too small rotor blades to load it properly.

My carb. just says "40C" I donīt know what that stands for.

Do you know of any web link related to this problem? is the new 50 SX-H the same?

What do you suggest?