How to tweak an OS 25fx for 2548
Moderator: hbartel
How to tweak an OS 25fx for 2548
I pulled the baffles on my 25FXs but the best RPM I can get is 13,600 on 30% heli fuel. Has any found any simple tweaks that can get me closer to the 14,500 limit?
- Ed Kettler
- Posts: 3437
- Joined: Sat Dec 15, 2001 6:05 pm
- Location: USA
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At the NATS all three of my Lim B engines (same limits as 2548) were exceeding 16K on 15% fuel.
I dropped the nitro level to 10% (all I had) and replaced the baffle-less mufflers with intact stock ones and I was still hitting 15K. Had to lower ATV to bring them under 14.5K.
Have now found that a MA 10x4 prop will drop rpms by 300-500. I was running APC 10x3s.
Have to wonder how that engine has been broken in/run to be that weak.
I dropped the nitro level to 10% (all I had) and replaced the baffle-less mufflers with intact stock ones and I was still hitting 15K. Had to lower ATV to bring them under 14.5K.
Have now found that a MA 10x4 prop will drop rpms by 300-500. I was running APC 10x3s.
Have to wonder how that engine has been broken in/run to be that weak.
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- Posts: 1009
- Joined: Tue Aug 09, 2005 2:33 pm
- Location: Middle of f'n nowhere
I broke the engine in with the run rich and pinch it up about every 15 seconds for about tanks method which has sworked good for me in the past. I tinkered for about an hour today testing different things I settled on removing the head shim, removing the muffler baffle and using 30% heli fuel. I am at 14,200 and will probably gain a little more when I put a fresh balanced prop on (I buggered one today)
I think part of the problem is the time of year. In So Fla it is about 97* and 85% humidity every day.[V].
I think part of the problem is the time of year. In So Fla it is about 97* and 85% humidity every day.[V].