I have discovered that I like "Bigger is Better"
sixty sized engines. I'm currently flying a Ro-Jett .65,
several S.T. V.60's , a Merco.61 and even some old
Veco/K&B 61.s. The problem is that all of these engines
are out of production and getting rare. ( Ro-Jett excepted.)

   This year at Brodak's, the Avistar .61 C/L was winking
at me from the display case and I bought it on an impulse.
My Scottish grandmother is rolling in her grave!
  I think it was about $130.00 after discount and taxes,
so not expensive.
   My intention is to use this engine Box Stock, then if I'm
not happy to hemi the head and try different venturis.
Everything I'm writing here is about a completely stock
unit. The only modification was installing the 0.1mm head
shim that comes with the engine.
   There isn't much information available about this engine,
except Bob Zambelli's first impressions so I'm being specific.
Since it's a .61 I started with prop, fuel and plugs as
Sparky and others recommend for S.T. V.60's.

Plug - Fox Hot Idlebar
Prop - Rev-Up 13-6
Fuel - Power Master 10/22 50/50
Tank - 6oz clunk on muffler pressure
Muffler- Stock as supplied

  The Aviastar .61 is a light engine for
a ball bearing ABC. Mine is 11.8 oz without
prop or muffler but the HUGE stock muffler
adds a bit more. I intend to discard it eventually
but It working for now.

   For Break In, I used Randy Smith's technique
of a small prop (11-6) and short runs of two minutes,
alternating between four and two cycles by pinching
the fuel line
  .Before I even turned the engine past TDC
by hand I pre-heated the engine with a heat gun
to expand the cylinder closer to the operating tolerances.
The engine started easily every time and I accumulated
40 minutes on the test stand before I got bored.

  OK, Now this is the "Special Information" part. The photo
attached should show the Aviastar Instruction sheet.
It warns that ABC engines make a sound as they go past
TDC and that this doesn't indicate a defective engine.
  Holy Cow! Even after two hours of running it makes a
serious " CLUNK!" as the rod ends take up the slack.
It doesn't clunk during a quick flick but it sure does
with a slow turn over when the engine is hot from a flight.
This does not inspire much confidence!

Now the good news.....

  The engine has about twenty five pattern flights on it
by various club members and we're all amazed how good
this engine is. It is currently mounted on our club engine
hack plane which is a profile Magnum tipping the scales at
72 oz (!!) with the Aviastar. . The huge beer can muffler
helps balance this fat beast.
   Even at this weight the .61 pulls it through the pattern
with authority. It isn't in the same league as a P.A. or a
Ro-Jett but it's pretty darn good. It doesn't sound as nice as
a V.60 either. More like a steady hummmm.
   One flick starts are normal (cold) and it starts well hot.
   We're launching at about 9,000.. just bubbling between
a four and a two and this leans to a wet two in the air and
then it stays there at a wet two. I haven't experienced
any surging or running away. Very steady runs where I
can concentrate on flying and not think about the engine.
This engine needles extremely well, IMHO.
  I haven't experimented with props yet but in 10 to 15
MPH winds the 13-6 seems good.

   So, in my opinion, this is a nice engine at a good price.
I like all the power and I love how easy it is to use.
   For me the CLUNK is an issue only because I worry
if the engine will last. The only way to know is to fly it
and so far I'm optimistic!
 

  I

Who else is using the Aviastar?

I've just today put about an hours running on my new Aviastar .46CL. So far I am impressed with it. You are correct about the pinch at the top, mine has a mighty clunk to it which I guess will ease with more running. I am going to be putting it in a Super Master. Which I'll be starting on once my Banshee is finished and in the air. Should provide plenty of grunt for it. Great value for money in my opinion.

Another 60 size inexpensive but good running engine is the Evolution 60.  I have 2 now and they both run very well.  On initial break in they tend to not want to drop back to a 4 cycle after going into a 2 cycle but that tendency goes away, for me, after about 1 hour bench time and a few flights in the plane.

I would not hesitate to recommend this engine to anyone.  Consider giving one a try.

although i agree, that engine is discontinued. so buy them up now! lol
http://www.horizonhobby.com/products/60nx-control-line-engine-EVOE0605

That link says no longer available.  I have one still in the box.  Wonder why they stopped making them.  Problematic or low sales?

when i called about it to verify if it was in fact discontinued, they said yes. because of low demand.

 I believe it was a rod failure. Deleted the email after several months. Had decided to buy an Evo.60, now they're gone. I'm going to Cincy to a swap meet this weekend, might find a ST60 or a .46