To my knowledge the #4 that's 6v. is the troublemaker with the "step" at/around 2200 rpm. That's what comes with the DLE 20's. - or used to anyway. I don't know anything about the 8.4v model. Are the new ones coming with that now?

The #3 6v. module, I'm pretty sure has the same "step", but it's at 25 or 2600 and isn't any trouble at all on the DLE 30's. Most won't even know it's there? Still, I would not buy a #3 module to replace the troublesome #4 module.

Any other Excel (or Excel knock off) module, other than the #3 or #4, as long as it fits a CM-6 plug you're good to go. It'll plug right in and run as is.

I'm fresh out of thoughts to help distinguish between problems associated with the timing step vs. those caused by engine temp./mixture. The fact there are 2 different problems so closely related is what makes this timing thing such a big deal with guys coming up to speed with gas. Guys with experience even struggle with it the first few times they run into it - even without this # 4 module in play!

It's hard to improve on kmeyers advice to just keep it rich on the idle. If it's a smooth idle you've got, it's too lean. Should be kind of lumpy, uneven when right. I would add that keeping the idle speed down below 1900 or so will also help. Higher can aggravate the trouble.

There is some help available for those messing with the "all in at half throttle" issue. Another lesson for the gas newbies to get past. Here's the link, but it's located up in the sticky up at the top of the gas section here, titled "Newbie to Gas Information". First page, down near the bottom of post #22. There's a series of diagrams that demonstrate how you can set your linkage up to take care of the problem, or at least get it close enough to allow you to dial the rest in with your radio. Holler for help if you need it!

http://www.rcuniverse.com/forum/m_8673009/tm.htm

Mesaflyer, we're good! I get how frustrating this can get!