Is there a problem with putting the Ignition Unit inside the cowl? Is the heat there too much? I have two MLD-28 Engines and have their Ignition Box's mounted on the side of the motor box on the side opposite the exhaust. They are mounted on foam with velcro. I have a very old 3W 60cc in an Aeroworks Edge that is mounted inside the motor box, really inside the fuselage.

Opinions, photos of mountings.

Opposite the exhaust, away from the majority of heat is ok. Inside the engine box is better. 3w ignitions are highly susceptable to heat failure so greater consideration should be provided them.

I do have my throttle servo mounted on the bottom of the motor box sticking up inside the box. Any interference issues with getting the Ignition that close to the servo?

Some will argue to the contrary but my experience is no, there is no problem as long as you follow established procedures avoiding metal to metal linkage contacts and secure the cap correctly to the plug. I would not go out of my way to lay the spark plug cable on top of the servo, but generally there are no problems.

Despite the drivel to the contrary you may hear from others, follow the advice above and you will be fine and well within current safe practices.

Agreed +1.

My small 30 size YAK has the ignition battery on the left side of the motor box, the radio battery is on the right side and the ignition module is on top. Throttle servo is inside the box close to the firewall. All wiring dresses in different directions and none of the wires cross each other. Works great!

I make a habit of placing the throttle servo, ignition, ignition battery, and ignition within about a 6" circle. Typically the throttle servo, engine and ignition are within 3" of each other. The battery will always go where balance requires it. However, I use only quality parts that have never been crashed and proven to be functioning correctly, secure all the connections, no metal to metal contacts, and assure the spark plug lead is correctly secured to the spark plug and does not rub on any other component, including the cowl.