Hi! I got a duratrax axis, with the stock .21 motor. It has already been broken in by the previous owner with 8 tanks, and I have it idling fine, but this is my problem. When I start it up, it will idle fine, and then I give it some gas, and it goes good, but once i am at 75% throttle it seems great, but then I go to %100 and the engine bogs down, and almost cuts off if I don't let go. When I am done running, I shot off the engine/servos, and and with the carb at idle(when I turn it on), while still off, (but still hot), fuel seems to start to fill up the carb and boil over. Also, I can't ever start it up immediatly after shutting it off(aka restarting). It also always seems to flood. Can someone help me? The engine never gets hot(i don't have a temp gauge), but my spit almost never boils off the head. The clutch gets hot, and also the pipe too. Thanks a lot.- zack

The first half of your post with your 75% and 100% throttle and how engine ran makes me think it's too lean on the main needle but not enough so that is totally cuts out, so try richening the main needle 1/4 turn and see how that works out. The last 1/2 of your post confused me and you said something like the engine wasn't hot enough to make your spit bubble off of the engine's head, so from that it could be too rich and doesn't have any heat in the cylinder. If main needle is too lean and at full throttle is cuts out like someone is turning engine off and on or it slows down a good amount then main is too lean, If it slows down but is burbbly and rough sounding and good amount of smoke out of the pipe then main is too rich.

Well, like the thread said, it was strange haha..
Let me revise....
1. The engine idles good. When i pinch the fuel line right next to the inlet for the carb, it will barely rev a little higher, and last about 5 seconds then quit.
2. When running, like I said earlier, I think low end is good, but when I go from about %75-full out throttle, it bogs down. I have never actually tested what will happen if I continue to hold down the thottle, or if It will shut off.
3. After my run, (about 8mins), I can spit on the head, and it will usually not boil off. It will take a while. The pipe is real hot, like it should be, and my clutch is sorta hot. I can hold my finger on it ofr a min or to.

I will try richening. I'll LYK. - Zack

My guess is air leak from the Dust Protection when you 100% throttle....