Is anyone running the Stalker 66?  I would like to know a basic starting point. Head shims, fuel type and how much? I am currently running a 12.5x 5.9 2B carbon fiber prop. I have a 5.5 oz tank installed but seems to not need it, maybe a 5oz? I have not been very successful in getting consistant runs, but that could be self induced from trash in the tank from soldering.      Thanks in advance.

A bit more information. I had some strange runs then I changed the glow Plug to an IDLE BAR  type and changed fuel

to The Powermaster blend Castor /Synthetic. I think it has mostly Synthetic. The the engine purred like a kitten

flight after flight. It did not like more rpm than 8600, al;though I have a Bolly 2 b 13" repitched to 7" due to the

weight  of the plane , and guessing based on the .Stalker 81 performance. What specifically are the

run characteristics you are having problems with?

Hi Walter, Just wanted to ask you if you are using the stock venturi? I am having real weird problems. No more crud in tank,no more leaks in tank, but during flight the engine runs and breaks hard inverted,I have shimmed the tank where it is now 7/32 in above spraybar inverted. The engine also loads up and almost dies on a hard pullout upright. This is very frustrating. What kind of tank are you using?

Jim,
Thought I'd add a bit to this thread.  I've been running the 66 this year at the urging of Brian Eather.  I'm flying the older version of Brian's Firecracker design with about 770 sq. in. The plane weighs in at 68 oz.  My Stalker is running an Eather 12.5 X 5.25 3B with slight undercamber on Powermaster YS/Saito 20/20 fuel which is all synthetic. Thunderbolt 4 stroke plug.  RPM is set at 8200 on takeoff.  The engine uses about 4.5 oz. of fuel for the pattern feeding from a metal uniflow tank and using muffler pressure.  The engine has a slightly different muffler than the one that Kaz supplies with the engine.  Mine is more like the Stalker 81 muffler but has a baffle in it.  I'm using 3 shims under the head and using the smaller of the 2 venturis supplied.
I've heard some stories coming mainly from Australia about poor runs on the Stalker 66.  Seems that the hard break and not switching back to 4 stroking seems to be the primary problem.  While my engine does not do this, it is common enough that some engines were sent back to the factory to find the problem with no resolution.  There is also, I understand some differences in the port timing on some of the engines compared to others.  Minor changes but none the less, differences. 
I'm certainly not trying to scare anyone about the engine as I love the one I have.  I was looking for a good replacement for my aged ST 60 fleet and thought I'd found it, but I will have to think seriously about buying another if there is indeed a quality control problem.
Alan Resinger

Alan, I have E mailed Kaz and he said to try a bigger venturi. While Im waiting for it I put a little bigger one in from another Stalker.The runs were improved. Yes it had the hard break and not returning to 4 cycle.Kaz says they are running big venturis and 12x6.5 pitch props at a low rpm. The bigger venturi seems to help. I went back to the two blade.I only got one with this engine .281 dia.     Thanks for the help.