Virgin run of my new OS FS95 Four stroke

Wow, what a big powerful engine. I love the sound of the 4-stroke. I've never flipped a 14" prop, you really gotta respect that thing. Thanks for the video.
Rusty

Yes, especially those APC's, they have really sharp edges.

Nice run Bandit, thanks for sharing.

Bob

Thanks Bandit ; That's one Smooth running engine and boy does it like the fuel I know OS don't usually require much break in , you said your going to run just one more tank after cool down and then the plane ? I have a OS 45 something that I have never ran but still holding on to she's brand new too . Eric

OS Max FS (= Four stroke) are beautifully built engines with utmost fuel economy. I have two OS Max FS 56 alpha  engines...alpha stands for the new design of the crank gases exhaled into, instead of the atmosphere through a vent, to the engine head where the cams are, ensuring lubrication of these parts that used to be starving of oil in older designs.

My instant observation - apart from the beautiful 4-stroke purr -  when starting up first time the OS FS was the exhaust gas carrying blackened castor oil... not the honey brown stuff our COX engines emit ..my fear was that was related to excessive wear of aluminum parts, the conrod or the piston in particular (like we may observe with COX engines running on unbalanced props eating away the aluminum crankcase, etc.), but with time I learnt the black smear is simply indicating the castor starts to burn at such compression rates/combustion temperatures that come with these 4-stroke critters.   Sorry but I was new to 4-stroke model engines that time.

My other observation was that if you do not thoroughly clean the throttle drum in the carb after your flight session, (which is not always easy in the engine cowling of the plane) the castor will tend to freeze-lock the drum and next time you want to start it up the throttle arm will not move easily. Some people say syntetic oil that does not thicken with time suffices for these engines unlike COX-s that are happiest with castor because of the ball-joint of the conrod. I remain kinda castor worshipper even for 4-strokes...

Enjoy yours, with its ringed piston and at least 18% lube in the fuel this engine will virtually never wear out..

It's running rich so it's gonna kill a tank pretty quick, that's a 12oz tank btw. Once it breaks in and loosens up a bit, it's fuel consumption will go down. It's going on my old Pica Rapier RC plane which I built back in 89 should love this engine!
fourstrokes can be big biters hand flipping them easiest way is to bounce it backwards and off it goes! and

@ rsv1cox:
You got that right, the most dangerous part of an ACP is it's dang tip, you can cut a steak with the tip so gotta be careful

@ Balogh:
Yeah fourstrokes are kinda a different animal got to be careful about needle settings too since they respond differently and are difficult to set by ear. They are best set with a tach reason why is because their RPM will peak before they fully lean out and will begin to detonate.
I usually run two stroke fuel in mine mostly 15-20% low viscosity heli mix which has around 19% oil mostly synthetic. Castor is fine for four strokes just don't go too high on it since varnish build up is a real danger in them due to their higher operating temps as you said and can end up sticking rings and valves. after run oil is a must in them since they are also more susceptible to rust and corrosion, a little squirt in the breather nipple and through the plug hole at the end of the day then work it through is fine. I love fourstrokes in RC models much more realistic sounding and are in general better on fuel economy. I have several, three saitos FA80 FA91S and FA100T odd fire twin, ASP FT160 twin Boxer style, OS FS90 (somewhere) FS91surpass and now the FS95v! (Bandit)

That's an excellent choice in engine, my first four-stroke was an FS90 back in the 80s then later on added a FS52 both are great runners with brutal torque for going vertical till out of sight if not careful :-).

Your engine sure started and ran easy that wasn't case with my 90 but the 52 started and ran just like yours, but the 52 was 10+ years newer.
I run 15% nitro most of the time.

Hey Bam
I never got around to your first thread, but welcome to CEF.
Rusty