I have an OS .61 in my Edge 540t. It runs good, however, the transition is slow. I can throttle up no problem, it is just slow getting there. I don't have any issues with the engine except for the transition. Can you guys point me in the right direction in getting this sorted out? Thanks

You could try leaning out the low end a little

It should take about 1 second to smoothly transition from idle to full throttle. Given that the high speed needle is correctly set then Mike's recommendation is right on. To do that, have a long screw driver with a blade that fits the low speed needle adjustment screw on the inside of the throttle arm. To lean it out, turn the low speed needle in (clockwise) 1/8 turn (no more). Let the engine idle for 5 or so seconds. Advance the throttle off idle to full. If it was rich on the low end the throttle should respond more quickly. Repeat the sequence of 1/8 turn, rest at idle, advance throttle test until the throttle response doesn't improve. Back it off the 1/8 adjustment and retest. At the end, your engine should smoothly accelerate from idle to full throttle in about 1 second.

Hth,

Btw, after tuning, my OS 61 FX performs this way.

I will have t try adjusting the LSN. Did your .61 have the same problem when you got it?

BB - don't recall exactly but don't think so. When new it went on my Kadet Senior kit. It was torn it apart as part of clean up following demise of the Kadet. I've had it on several other planes since. Bearings have been replaced. What I'm saying is that I've gone thru the drill several times with this motor (and every other 2-stroke & 4-stroke) that I own. Just consider it to be standard setup. I fly at nearly 6000 feet. No manufacturer's initial settings work without tweaking.

Bonebreak, If memory serves me correctly, ALL my OS engines came from the factory with the LSN set rich, including the .61!
Tune as described above.

If the engine is new or has little time, when you adjust the HSN...set it just one or two clicks rich from "full-scream". Dedicate your first few flights to help "break in" the engine.

I had this plane on my Extra 330, and now in the Edge. It has about 1 gallon+ ran through it. It has always seemed to have a slow transition. It really became noticable when my buddy got his 55ax. The transition on it is twice as fast as my 61. That is with factory setting on the 55ax.

What prop, glow plug, muffler, size fuel line and fuel are you using?

The pinch test will tell you if your LSN is too rich or not.

1.Warm it up.
2.Go to full throttle for a few seconds to clear it out.
3.Go to idle and let it settle in.
4.After awhile pinch the delivery tube to stop all flow.

If the engine speeds up just before stopping, it's too rich. Adjust the LSN about 1/8 turn in. Start again at 2.

If it just suddenly stops with no speed up, it is too lean. Adjust the LSN about 1/8 turn out. Start again at 2.

It should barely speed up and stop when it's set perfectly. Don't sweat getting it perfect.

I am using an Evolution 12X6 prop, OS A8 glow plug, Stock muffler, standard fuel line, and Wildcat 80% syn-20%castor 15%nitro/18% oil.

OBTW - once you get the slow speed needle adjusted you will have to go back and readjust the high speed needle. Also, the throttle trim / throttle stops in the radio will need to tweaked as the idle will probably be higher than is was before.

Another point - after you think that you have it nailed remove the juice to the igniter at idle and see what happens. I happen to use a Hobbico panel on my field box. It has an adjustable glow plug igniter with a dial on the panel which allows me to vary the juice to the glow plug and entirely turn off the juice without removing it from a running engine. If your low speed adjustment is spot on you should be able to remove the igniter (turn off the juice) and let it idle for 30 or more seconds without loosing any rpm. Yes, it may load up a bit and need some full throttle exercise to clean it out but there will not be any noticeable drop in rpm. If there is a drop in rpm because the excess fuel is cooling the glow plug - adjust the slow speed needle 1/8 turn in (lean it out)and test again.

Ya can't do this on your work bench. Go to the field, mount the wing (planes aren't built to take engine torque without the wing mounted - please don't ask), fill the tank, and start playing with the jets. If you have a buddy with a tach - just some additional information to help tune that engine. Just watch out for that prop!

Once you have it running correctly, kill the engine, gently screw in the high speed needle until it hits the seat - counting the exact number of turns and fractions of a turn - write it down - then back it off that many turns. Gently screw in the low speed needle until it hits the seat - count the turns, record it and then back it out. Now you have a record no matter how many times that you bump or accidentally adjust the needle settings.

Em - electrics sound sooooooo much easier and much less messy ...

Good luck.

Those components sound fine.

Actually, what da Rock suggested eliminates the guesswork.