question on RPM's

[Mr.E]

i was able to get my new engine started yesterday, . but i was a little concerned with one fact, which was the rpm's it was turning. its a Brison 6.4 twin with a carbon fiber 24X10 prop on it(not sure what brand prop as it was already on when i bought the engine). at idle it was spinning 2100 rpm, at full throttle it was capping out on 61-6200 rpms. to me this seemed a little bit of a low number being that from idle to full was only a 4k difference. since you guys were such a huge help to my question yesterday i figured might as well get your thoughts on this question as well

[Flyinrazrback]

That motor should pull a 26x10 at the rpm that you are getting with the 24x10. Is the carb opening all of the way? Is the motor running rich?

[Mr.E]

i apologize, your are correct it is a 26X10 prop on it, the carb is opening fully and i am running 91 octane with 40:1 ratio on the oil mixture. i was told that it would be best to run this mixture on the engine to make sure that the engine gets fully lubed up being it has sat for 6+ months.
Just a side note, my home town is Temple,tx. in fact be down there next weekend

[Biff]

Sounds like your top end numbers are about right. 6K is a good number to prop the motor to. 2100 is a BUNCH of RPM for idle. One thing you will notice about gas burners is there's a sweet spot near idle where your plane isn't in a harmonic. Extended idle isn't something I let the plane do on the ground. It's pretty tough on airframes and servos. Is the idle stop still in the motor? It's a small adjustment screw that keeps the butterfly from closing too much. I take it off and pitch them. That way you van kill the motor on the idle trim. The Brison also has a mechanical advance. Make sure it's not binding. I've had some serious issues with another brand motor with the mechanical advance binding after the motor came up to temp. The Brison is an excellent motor and should idle down nicely. Just be easy on extended idle for your plane/electronics sake!
Glad you got the beast cranked! Any problems? I gotta salute you for asking the right questions! Too many guys just cowboy up and let her bump. Biffy proud!!!

[Flyinrazrback]

Bring the plane down to Temple!

[Mr.E]

To answer your question Biff, the idle stop is out of the carb and i can kill the engine with the idle trim. to my limited knowledge there seems to be no binding of the linkage. Since you said that this seems to be a Bunch of rpms how do i slow this down or is it a major concern for me?

and for your other question absolutely no problems, did the choke sequence Jeeum suggested, flipped it 5 times and it popped, opened the choke on the 3rd flip i screamed "She's Alive" thanks again for all the advice from everyone

[Kiwi]

2100 is way too high for idle and I doubt you would get the plane to land at that rpm. It would still want to fly. You should be looking at anything from 1000 to 1200 or so. I have a well run in very sweet ZDZ 160 that will idle at 700 and not miss a beat but thats not normal.

I would think your servo arm probably needs backing off one spline or the ATV on your radio needs opening up. A good way to set your radio is have it so when you put the throttle trim to zero your engine quits. One way or the other YOU MUST BE ABLE TO SHUT YOUR ENGINE OFF FROM YOUR RADIO. Some sites wont let you fly if you cant and it makes perfect sense.

So putting it all simply set your radio with the trim at zero so the butterfly is totally closed. Then set the other end with the throttle at full and the trim in the middle so the butterfly is fully open. Dont go past 90 degrees or your starting to close the butterfly again. Do all that with the engine off and your eyeball looking at the workings. Once you get that lot set you can fine tune it all later. Depends if you have throttle curves etc as to how you like your engine to respond.

Patience is a real virtue setting up your engine and it will pay big dividends once it is set right.

Kiwi