What is wrong with an outboard motor that won't run unless its choked?

Question

Its a 2004 Yamaha 4 stroke, possibly fuel injected

Answer 1

There is probably trash in the carburetor(s) and the mixture is too lean unless the choke is on.

Answer 2

Previous answers are both right. Let's examine the principle of "choke". The choke restricts air intake, but not fuel... therefore creating an excess of fuel. This is called "rich" mixture. So if your fuel lines or carb or injectors or whatever (doesn't matter what kind of engine) are clogged or otherwise impeded, and you are not getting enough fuel for proper ignition, it would be running "lean". Choking it fixes this symptom, but not the problem.

Answer 3

If it has a choke it's not fuel injected. Your carb needs to be worked on. Most times they sit and the gasoline inside them turns to varnish and gums them up.