I purchased a ST 61 ABC new this summer. To date it does not seem to develop the power I expected. It starts, idles and transitions fine, but it just does not seem to get up to RPM very well using either Omega 10 % or Omega 15% fuels. All my other engines are running out of the same fuel bottles just fine. My question is how long does it take to break in one of these engines? What RPM Should I expect turning the 11 X 7 prop recommended in the specs? I did all the normal troubleshooting like removing and sealing the backplate and checking for air leaks around the carb base, etc. I've been in the hobby four years.

I was very careful to initially break it in per the instructions. It was run rich but not four stroked a few minutes then shut down and allowed to cool and then restarted and run over and over again for at least four tanks of fuel before it was mounted in the plane.

I have it installed in a 60 size Pattern trainer that weighs about 7 pounds, maybe 7 1/2 pounds. When it takes off it acts like its dragging the airplane into the air. Once it gets to altitude and starts down, the RPM seems to come up some. I have a MAS 11 X 6 Prop on it because it won't turn an 11 X 7 well at all on this plane. It is set up with the stock muffler, there have been no modifications. I don't have exact RPM numbers but could get them if it would help.

Frankly either of of my 46 size engines will turn an 11 X 7 prop better than this guy is doing. I have a ST GS 40 that runs great which is the reason I decided to get this one for this new airplane.

Your help here is appreciated.

John Mecalo

Your ST 61 may need a little adjustment to the spray bar. I helped a freind with his ST 61 which he had purchased used
with Hanger 9 Pizazz. His problem was lack of power and
unable to lean out the engine enough. The instructions with
my ST 3250 make a small reference to adjusting the spray bar.
The position of the cats-eye in the bottom of the spray bar
affects the fuel draw. The two small screws on the left side of
the carb. allow you to change this. You may need to mark the
current posistion of the spray bar as your starting point then
adjust two or three degrees and then run your engine. My
freinds Pizazz was a little heavy too, but the ST61 pulled it
fine after we made one adjustment at our flying field a couple
months ago.

John,

The SuperTigre .61 ABC should easily turn in the mid-12,000's with an 11x7 propeller. Make sure the slot in the spraybar is pointing straight down into the carb. You can also richen the idle a LOT. Get the high-speed needle adjusted and then work to get the low-end set. We always start out with the low-speed needle set so rich that the engine won't idle. We start at 1/4 throttle or so, advance to full, set the needle, and go from there.

Also, ABC engines should NEVER be run in 4-cycle mode. A brand-new engine should be leaned just enough so that it stops running in 4-cycle mode. You then can lean the high-speed needle as the engine will accept it.

The Omega fuel you're using is fine. 10% or 15% won't make much difference at all.