Glen, That's whet I've always heard also..

I appreciate your answers, guys.  My 61 is vintage late 60's.  It has a black head and bright silver fins, with a 4 bolt backplate, and a single ring.  I had to get a Kavan carb for it because the needle valve on the old one was damaged and I couldn't find a replacement. I'm looking forward to using the engine.  Thanks again.    Glen

The only twin plug engine I've actually run is my son's OS H-80 and putting power to the second plug once it's running makes no difference to the revs. It's always been held that the second plug automatically begins to glow once the engine is running and the only way I can think of to find out if it really does is to check the resistance of the coil between not running and running. If it glows then presumably the resistance would increase (if my very limited knowledge of things electrical is correct ).

As for Mercos, I have 3 of the larger ones (and 2 of the .35's). One is a Merco 49 Black Streak (two plugs), one is a Mk2 .61 (light case, two plugs and brand new) and the latest is a Mk1 .49 which was given to me by a wonderful old guy near Nashville. His spare brand new 49 crankcase arrived yesterday. The story behind this engine is that many years ago (and it must have been 1962) he was in a London hobby shop having a cup of tea with the owner when a Merco rep came in to say that the new Merco 49 was now available. My friend immediately said he'd have one and went back the next day to pick up his engine. So it's one of the first (possibly even the first) Merco .49's ever sold commercially, still has an extraordinary compression seal and starts first flick every time .

To further bore everyone with the story behind my Merco, In 1971 ( I think), I bought the engne to run in a DeBolt Jenny trainer that I built.  I also built a Heathkit 4 channel RC rig to put in it.  Amazingly, everything worked, except the pilot.  After several take-offs, but no successful landings, the plane was trash, so I put the radio and engine away.  I subsequently used the radio in a couple of other planes, but as an effect of several moves (Army), the engine went missing and I gave it up for lost for over 30 years.  Then, a while back while I was looking through some boxes for a slide projector, I found the Merco and a Torp 35 ( still haven't found the projector, but maybe St. Anthony will help me with that, too).  Ramblings...........................Glen

Ran her on the stand, today.  Third flip start; good, rich 4 cycle for about a minute, then leaned out to a rich 2 cycle at the top end; back down to slow idle for a few seconds; transition back to top end was smooth for a rich high-speed needle setting.  I ran Powermaster 10/22 (11/11), and the engine seems to like it.  The engine had a butterfly baffle on the exhaust, but I was able to fit it with a header and muffler from a ST G51 (bulky and heavy), which seemed seemed to be compatible with the engine, as it didn't seem to overheat.  I'm happier than a pig in a big bucket of clabber!!! 

Glen