Need help on 740

Got a 740 that will only run with choke pull half way out. What should I look for first?

May sound odd but check the spark first. It needs to be a blue/white and jump a 1/4 inch gap or more. Next check gas flow by removing the carb drain plug and let the gas flow for a few minutes. Catch it so as to look for dirt water etc. Should be a good steady flow. Also it is always a good idea to check the air cleaner and make sure it is not full of water or dirt or both

As always, check the electrics before chasing the fuel. If you have a hand held ammeter, put it in line with the distributor or coil and see if the points are carrying at least two amps. If you have an ohmmeter, compare your coil with a known good coil (some Chinese replacements have insufficient copper wire inside to run properly). Pull the spark plugs and spin the engine with your thumb in each spark plug hole to check compression, and then clean/replace the plugs as needed. Spin the engine with the spark plug wires hooked to the plugs (and out of the engine but still grounded). There should be a pretty hot spark across the plug's gaps. Pull the air cleaner off. Pull the gas line (past the fuel filter), turn the fuel on, and see if you have a respectable flow out of the gas line into a catch can. If still running poorly, pull the carb apart, and run a small soft wire through all the fuel passages, then flush with carburetor cleaner, then adjust the float level, while insuring that the needle and seat moves easily. Then, dump all the fuel out of the fuel tank and run some fresh fuel through the fuel line and into the catch can. Reassembled, the tractor should run OK.

as said. alsways check spark first. it may not ( likely not ) it.. but it's cheap / free and fast.

pas tthat. check fuel flow to carb... and finally.. check the carb.

my bet is on dirty main circuit in carb.. or highly restricted fuel inlet