"Reading your Glowplug"
Keeping an Eye on your glowplug will help you to understand how you should adjust your carburation.
1) Take the glowplug out and look at the coil element :
if the spiral is a little bit pressed and bent it means that the engine has too much compression. If you are racing on a sea level track, with 25% or more nitro this could be the main reason. Than you need to check underhead shims and insert a tenth.
2) If the coil element has a dull, as if it were sanded, it means that the carburation is too lean (lack of fuel) and you can damage the engine. You run the risk to break the coil element and make it fall down on the top end of the piston, damaging the piston/sleeve. In this case, you should replace the old Plug with a new plug and richen the High Speed needle 1/8th.
3) If the thread has a dark colour and the plug seems wet, the carburation is too rich and the engine isn't running at optimal power. You have to lean the carburation closing the High speed needle.
4) When the coil element is polished and the spiral does not present any imperfections, your engine carburation is most likely spot on.
This, along with increased experience in learning the "Sounds" of a glow engine and use of a quality temperature guage, will make you an Ace at tuning your engine... Tuning your Models engine is not "rocket science" and is fairly easy once you completely understand the how the carb works and the effects it has on your engines performance and sound. With some time and experience, it will become second nature to you... just be patient and perseptive and the knowledge you gain will take the voodoo out of this great hobby! Enjoy...
