Hi folks,

Just wondered if anybody was familiar with an engine that my friend described to me over the phone.

He picked it up in a trade deal and doesn't know much about it.

He said it's an O.S Max .61 with a gold head and (special edition) stamped on the mounting flange.

It has a side exhaust.

The "61" is marked on the exhaust port side and "(special edition)" is marked on the mounting flange on the other side along with O.S MAX on the casing.

We think it's similar to the SF series. It's an ABC motor.

The carburetor has the Low speed mixture screw on the same side as the High speed needle and it (low speed screw) has an elongated head held in place with a flat metal U clamp.

Any help is appreciated[8D]

You are asking about an O.S. Max .61 FSR ABC Special Edition. This was a limited-production re-release of the .61 FSR in the 80's, after the .61 FSR had been discontinued.

Ol:

I have this engine in an Astro Hog Biplane. Bax described it as I remember the engine when I bought it. My engine is great. Idles well, has power and is very dependable in flight. When O.S. put it out, it released it as a limited edition engine. It was expnesive for its time and I have never seen it advertised since then so I assume O.S. has not re-intrduced it. I still have the manual. If it ever came out again, I would buy another just to keep it in my inventory.

Capt Lou

What is the engine worth new in the box???

Ask a seller. We don't have prices for old, discontinued engines. We are not a reseller.

Also, this was asked on another thread. Please do not make multiple postings of a question. That's against RCU rules. Thank you.

What is the optimum needle valve setting on a os 70 fs low end sea level conditions.

There isn't a number anyone can give you. You have to find the setting based upon how the engine is being run. Usually, a high-speed needle will wind up between 2 turns out and 1-1/2 turns out from closed, depending upon the fuel and propeller used, and the day's current air temperature and humidity.