What are some of the symptoms? Does it start easy enough? Does it idle farely well. Is it just a transition problem?

Your highspeed neele may need some significant adjustment -- do that with the goal of getting your high-end in an optimal state, about 200rpm below maximum sustainable. Once you have a good high end make minor adjustments to your low-speed wheel to smooth out the idle and transition. Minor adjustments should be no more than 1 1/2 ticks from neutral.

A couple of other things to consider and check:

1) Make sure you fuel system is large-bored, fuel line, klunk, and brass tubing into the fuel tank. The tank should be less than 12" from the engine with its mouth vertically-centered on the carburetor.

2) What kind of muffler are you running. If it is a Bison pitts-style muffler, some of these large engines need more pressure from the exhaust tap. You can increase it by blocking off one of the exhaust tubes.

3) If your fuel system is not set up optimally you may need a regulator or pressure pump. The regulator works off of a crankcase tap for fuel tank pressure. This tap provides significant pressure and should not be used without a regulator.

4) I found that the OS 4-stroke, Type F, plug to be an optimum plug for this engine. I have also found that the Moki is sensitive to good quality glow plug.

5) Probably more important than anything else; is the Moki is a low-compression engine, dessigned to be run on little or no nitro. Unlike the large Super Tigers, this engine should not be run on a low-oil mix. Keep it at the 18-20% range. I run Omega FAI fuel (0% nitro and 18% synth/castor (80/20) oil.) and when that is done I will mix up a batch of Methonal and mix it with 20% Klots. I don't care that my muffler looks old before its time from the burnt-on castor.

The Moki 180 is a ringed engine. If you have somehow damaged it by running it too lean you should be able to see the damage to the sleeve lining and/or ring. Though not free, repairs are much cheaper than buying a new engine.