Here is the situation: New OS 25 FX engine on a test stand in upright position. Tank has a good seal, clunk and vent line properly installed and hooked up. Tank midline is even with the needle valve. Needle valve closed then opened 1 1/2 turns. Prime the engine, connect glow starter, flip it a few times and the carb fills up with fuel and runs out the carb opening. Any suggestions appreciated.

try not priming it. if it floods fast, your needle is too rich. it is possible, however that your low end may be too rich as well. i assume you are trying to start it at low throttle, correct?

I am trying to start it at a little above idle. How do I tell if the low end is too rich if it isn't running? Thanks

how many turns out is your low end?

I found the prob. The gas tank had to be moved down lower. Cranked up fine. Im on the third break in tank on the stand now. Runs great. Thanks.

but didn't you say that the tank's centerline was lined up with the needle? if it was you shouldn't haveto move it down and you have a different problem. you shouldn't haveto do that.