If electrical items are intermittent (all of them) then you best pay attention to the condition of the battery cables. Remove them, make them shiny clean and then reassemble them -- tightly. And remember there are two ends to each cable. Your failure to start problem is likely operator error since you don't know you have or how to use the fast idle lever. On the top of the throttle shift control is a flat lever. For cold starts you raise that lever up. This allows the engine to idle faster after startup. Your engine has a primer system -- not a choke. It injects a bit of extra fuel when you hold the key in when starting. It also has a primer bulb that you squeeze until it is firm. This pressurizes the fuel system for first start of the day/week/month. So here is the proper COLD starting procedure. That is the first start of the day:
1) Squeeze the primer bulb until firm.
2) Raise the fast idle lever about 2/3 up.
3) Turn the key to START and push it IN until the engine fires.
4) Release the key and then lower the fast idle lever a bit to let the engine warm up.
5) Be ready to bump (momentarily push in) the key to give the engine another shot of fuel if it tends to want to die during warm up. Don't wait until it dies. Be ready!!!
6) When the engine has a stable idle, lower the fast idle lever fully and go boating. With the fast idle lever raised you CANNOT shift the boat so do not try unless you want to break something.
With the engine warm, you should only have to hit the key to restart but again, use of the fast idle lever helps. You "generally" do not need to push in on the key on warm starts.