Starting problem with 2004 Mercury 50hp on recently purchased 21 pontoon boat.

When prepping to take boat to lake or bay to fish, will flush engine. When starting engine, key will turn over engine
and engine may or may not start. If I assist by moving choke linkage, it will start. Is the problem due to electrical, fuel
or adjustment issues?

Maybe I'm missing something in your description here, but you typically have to choke (or enrich) the motor to get it to start cold.

However, if I'm missing what you are saying and this motor is relatively new to you, what is the history on it.

Did you buy it from a dealer or private seller?

Has it been sitting around, unused, for a while (months/years)?

Did you do anything at all to it before firing it up after purchase? (new plugs, new impeller).

Did you see it running with the boat in the water before you bought it?

You could have old gas, old plugs, partially clogged carb, bad tank vent, bad gas lines, crud in the fuel filter or dozens of other issues.

Or maybe you are just not using a correct starting procedure - can't say from the limited info you have provided.

When you turn & push the ignition key in, you are choking the motor to start. The engine turns over but does not crank.

Purchased boat last year from marine dealership. Not sure as to how long it had been there. They did crank it & run it, after
replacing a ignition relay.

But, I did have Boyd's Marina in Dothan,AL do a quick check up before I took the boat out to just make sure everything was
okay. They replaced carb gaskets, made adjustments and replaced plugs.

I will say that I have not been taking it out on the water a