ORIGINAL: minny minoza
Scored two engines last nite; a K&B .20 Sportster, and a Norvel .25. Ain't sure if the latter's a big mig or not. Just has NV .25 embossed on the cylinder wall.
My Big Mig .25 has "BIG MIG" on the engine mounting lug below the .25.
The K&B Sportster .20 was replaced by the .28. I have two of the .20's. Note that the cylinder is AAC and does not have a liner. When the cylinder is worn out you would have to get it re-chromed or chuck it, so use an adequate amount of lube. If you got the whole package, it came with a muffler and a radial mount backplate.
Edit2: This is no longer true. Apparently the engine is being made again by K&B/MECOA and the cylinders (jugs?) should be available. Also, the new version has a remote needle valve assembly.
Good luck with both of them.
George
Edit: Forgot to mention, the NV .25 should have included a spanner wrench for the head.