So i used to fly this plane when i was much younger and i'm trying to get the thing going again. I've been fixing all the holes and stuff in it etc.

Anyway, I ordered a new carb for my OS .40 LA and it came, i slipped it where the old one was with a little rubber ring around the hole where i put the new one.

I put the two side screws in and that was it.

Now that its all together, when i try to get the engine going, it sounds like theres some kind of air leak. And after i'm spinnin it for a while the glow fuel starts to leak out. Did i miss something in the installation?

Whats the little screw with the spring on it do?

Read [link=http://manuals.hobbico.com/osm/40-46-65la-manual.pdf]this[/link]. Go to page 26 first. Much will be revealed.

The small screw with the spring on it is the low speed adjustment. You shouldn't have to touch it. I would pull the carb back off and make sure the gasket it seated right. I put a new carb on one of my OS LA engines recently after a crash and I put the O-ring on the carb first then mounted the carb on the engine and didn't have any problems.

pkevinb was close. He left out one important word in his description.

The small screw with the spring on it is the low speed MIXTURE adjustment. It screws in/out of course and in doing so varies the amount by which a small hole is open. If this has been tampered with reset it so that the hole is about half closed for a starting point otherwise leave it alone until it NEEDS adjusting.

Slip the o-ring onto the carb and then install the assy to the engine. Install the retainer screws loosely at first. Then, while pressing down on the carb to improve the seal, tighten the screws.