My 2011 evinrude etec is acting up I put it in the water the other day and it started right up and after a few min stalled and would not start back up ....I pulled spark plugs they was dirty and in bad shape I put new ones and and indexed them and put boat back in the water it fired right up but don't seem to be running right I noticed it spitting unburnt fuel out of the exhaust ....I'm wonder ing if its a coil or injector it seems to be running on two cylinders ......I'm thinking injector stuck wide open or coil not fireing ...help please