putt_13

My Feedback: (3)

Hello,
I have a Norvel BigMig .061. Its a great little engine. I have it on my GWS Corsair right now. Anyway, it has a great idle, mid range, and full throttle. However, when I fly the corsair around at idle for awhile, and then give it full throttle, the engine sputters, like it is sucking in too much fuel. This has never happened with my 40-sized engines. Why is this happening with my little Norvel? I'm running 20% fuel and a 5.5x4 prop.

I am asking because I plan on putting the .061 onto a little 3D airplane, but if I am hovering it right above the ground at half throttle, and then give it full throttle, to go vertical, and the engine sputters like that, its going to crash.

Thanx -Patrick

xanaphyst

My Feedback: (17)

I would try going to a 5.5+3 or a 6+3.....then tune it on the ground with a tach....richen it 300-400 off full RPM.
If that does not work try changing your glow plug. The Big-Migs are great little engines..

xanaphyst

ptulmer

My Feedback: (5)

For 3d stuff you may try a 6x2. It'll give you the thrust and rpms you'll want. The problem your having sounds like it's loading up. It's easy to fix on a standard two-needle carb by adjusting the low-end. I don't see how to adjust the Norvel for that. I remember someone around here had thread about adding an air bleed hole.

putt_13

My Feedback: (3)

Hello,
Thanx for the advice on the prop size. I will take that into consideration. -Patrick

zoomzoooie

Is you engine mounted inverted? This can cause excess fuel pooling in the glow plug and cause a week ignition that will cause sputtering if run at idle for any length of time. Since you say you are at idle I take it that you are in normal flight and the engine would be inverted if that is how you have it installed. Since there is no idle adjustment screw you should increase the throttle once in a while to clear the excess fuel. Also if your fuel tank is mounted higher than the center of the carb needle you should relocate it to be centered with the needle.

ZZ