I installed an os 37 in my raptor 30v1. I've read other posts stating engine was good right out of the box. I tried and tried to get the rpm's up after starting engine. No go. The manual says to set needle valve at 1.5 turns. Engine out of box was set at less than 1/4 turn. So I adjusted the needle to 1.5 turns. Started engine and managed a few more rpm. Butt nothing that could make heli light on it's feet. even at full throttle. The engine smokes alot literally dumps so much fuel thru the exhaust that fuel is flowing off the landing gear. I'm using 15% nitro very close to sea level.
Any tips on tuning this engine?

Lean it in a few clicks at a time till it starts producing power.

OS engines are great but don't make any assumptions.

Always snug the head bolts, pull the back plate and check for machining scraps and snug the back plate bolts when your done putting the fan and prop nut on.

Open about 2 turns out on the high and start adjusting from there. Every OS engine I've ever ran out of the box needed the low end leaned anywhere from a tad to a good bit, if your idle isn't smooth and transition is sluggish lean the low end a tad at at time but get the high end in the ball park first.

Hockey Thanks for the reply. I'm going outside to try again. I've set the high end by the manual. 1 turn. It was out of adjustment by 1/8 of a turn out,,, according to the manual. What are the symptoms that would indicate the low or high end needs adjusting?? Which way to turn?? I do know a little about adjusting the low end, butt little to nothing about adj high end.
One thing I can say about this engine over the tt36 is at least I can get this engine to start more than once before having to try adjusting carb. lol

When your hovering for a few minutes, land, shut it down and feel the back plate of the motor. If you cant hold your finger on it for 3 seconds its too hot and too lean. If its cold you can go leaner till it warms up. If its sputtering and throwing raw fuel out the exhaust its too rich, even for proper break in.

Hockey thanks again for a quick reply. I've got the idle set real smooth. low enough that the blades barely turn and engine has a smooth rhythm. Engine will build up speed butt not enough to get heli light on her feet.
After rpm gets just so high, well that's it. no higher. Can you advise. Thnx

Make sure your throttle is opening all the way and you have about 5 degree's of pitch and 50 percent throttle at half stick.

Ensure that your atv's are even away from center that is, dont have 60 left and 90 right, make sure they are matched or very close.

Make sure that the throttle geometry is correct, that at half stick the pushrod is 90 degree's to both the servo arm and the throttle arm.

Make sure your top end pitch is no more than 10 degrees and bottom stick is 0 to -2 all in normal mode.

Hockey thanks for reply. Unfortuanately I know little about what you're trying to tell me. Everything except engine should be set up correctly. I recently pulled the tt36 and put in an os37
would this throw off the setup of heli?

Lets say your throttle arm on the TT was open all the way at 1 oclock looking from the side of the engine. Now your OS is open all the way a 12. They are close so it might look right but your not getting nearly as much throttle on the OS as the TT. See where I am going with this.

Proper throttle servo to throttle arm setup are key to getting your heli setup correctly.

http://www.raptortechnique.com he's got lots o pictures.

I took the heli to a fly field today and received some help and learned a few things. Hockey you hit the nail on the head when you said dump the TT and get an OS. Thanks for your feedback and all your help along the way.
Dennis

No problem. Happy flying!

I'll take burning fuel to endless needle tweaking any day!
Andy