Gidday all
Can anyone tell me of a site or documentation on tuning engines. ? Im a noob to the r/c Aircraft world and just bought a worldStar-40F and am getting a used .40 in good condition. I have a background with r/c ic boats and cars but want to learn about "Air" tuning. Any help ?!??!?!!?

There are several pages regarding engines on my site. This page discusses "tuning."

http://www.airfieldmodels.com/inform...e_controls.htm

HI, FROGTWAT! First it's good to know if you have an engine and fuel tank setup that is tuneable. If you prime the engine through the exhaust port and then turn the prop until you are up on compression,that compression should not bleed off in 5 seconds or so. The next check is for air leaks out the back plate, or out the cylinder head. Prime your engine with caster oil, bring it up on compression,seal off the intake with a free finger, then dunk it in water. you should not see any air bubbles coming from the back plate, or from the head. The tank should be sized for the engine you are running. Too big of a tank and the differences in head pressure from full to empty can be too much for a little engine. 6 ounces is a good size for a .40. A pressure line from the muffler to the tank works 99% of the time. make sure that the tank has no other air leaks besides the pressure line. NOW we are ready to tune the engine! I like to set the high speed needle for the worst case scenario, which is when the model is pointing straight up in an extended climb. When you have it set for max rpm, it will be slightly too lean. you should be able to quickly pinch the fuel line without the engine sagging. On an older engine it isn't good to be this aggressive with the high speed needle, what you want to do is creep up on the setting through in flight trial and error. Most engines have only the one needle, and an air bleed screw for the idle mixture. Slow the engine down to the lowest reliable idle that you can manage. If you can't get the plane to idle low enough so that the plane doesn't creep forward on the ground, then we need to figure out which way to turn the airbleed screw. hold the model in your arms and raise the nose. If the speed increases, then you are too rich and need to turn the screw 1/2 turn counter clockwise. If the engine runs worse, then you are letting to much air past the screw threads and you have to turn the screw in.If you have a 2 needle carb, the low speed setting is similar, but you turn the needle clockwise to lean it .Some guys set the high speed needle with a temperature probe, but they are too spendy for me. Hope this gets you going!

Thanks for the link CafeenMan and the info combatpigg ill try these when the SUPLIER GETS HIS FINGER OUT !!!!! suposed to get the motor today but "he forgot"..... GRRRRR umm the fuel tank measures 380cc (whatever that translates to in your measurement) which the manual says is the right size for a 40. The tank is brand new, the engine........ im thinking the engine wont take any damage(from submerging it in water) because of the oil?!?!??! ( exhaust on or off ? )
So should the engine run better a little on the lean side or the rich side ?????
Is there a site that lists all the 40 size motors on the market ?
From what i remember of the motor when i saw it it had 2 needles a shorter one on the side the throttle is and a larger one on the other side of the motor (asume the shorter would be the low speed)... but i could be wrong! you know what its like when you see your new toy for the first time !

Should never run the engine lean,can also harm the engine by running the engine too rich,if you error its better to be a little on the rich side

If the engine is an ABC then you should run it "just right." Neither lean nor rich. If it's ringed, then a little on the rich side. Just point the aircraft straight up and lean it to peak rpm then back it off a couple clicks. That's about as perfect of a setting as there is.

HI FROGTWAT! [Great name!] The pressure check is made with the exhaust off, but if you want to get clever you could put the muffler on with some sealant, attach some tubing to the muffler outlet and blow into the tubing. If you cap off the intake, and make sure that the piston is down you can test the engine this way. If I'm lazy [which is always] I will attempt to fix a leaky backplate by spraying the area with brake cleaner, blow drying, tighten the screws snug and then wick some thin CA glue into the crack. Down and dirty. Aluminum paint can be tried to correct an imperfect seal on the head. You can try to hone a flat face on the top of the liner with a wetstone.A new head shim or gasket is the easiest thing to try first, of course. Over tightening the head screws can warp the head. I have a question FROGTWAT, do model engines run clockwise in AUSTRALIA?

HAHAHAHAHHAHA Yeah good one Harrasing a noob like that ! but it got me thinking And the answer is NO !!!!! (not if your looking at the plane head on !) I should be getting the motor and radio gear tommorow...
This is what she SHOULD look like (before i "matchstick it")..

[link=http://www.theworldmodels.com/para/products/airplanemodels/a113f.jpg]WorldStar-40F[/link]

i have a world star 40, it flyes well, better than my old vmar hotrod that i crashed (forgot to pull out the antena).

FrogTwat..........GOTTA LOVE THAT NAME.[sm=biggrin.gif]

http://www.rcwebboard.com/forum/topic.asp?TOPIC_ID=7488

Checkout my post where I describe engine tuning :-)