Is the Norvel a good engine? Does it take a standard glow plug? Or does it need a plug you can't get?
Are there different models? Or just 049, 061, CL & RC?
My NORVEL (Northern Velocity) engines run well. They had two types, the AME was for all-out performance and the Big Mig was easier handling. They were available in .049, .061, .07, .15, .25, and .40 (I don't have the .40).
The .049 and .061 used the same propietary plug, but the Cox glow head could be used, and they made conversion heads for 1/4"X32 standard plugs. I believe the AP head also fits.
The .07 used a propietary plug, the others used a standard plug.
These are now sold as NV engines. I do not (yet) have any of the new ones so I can't speak for them.
George