Rough running after pulling it out of winterization :(
 

Any ideas why my boat (98 Tige, Mercrusier 350 MPI) would be running roughly after the winter break? I had it winterized and it sat in a nice, indoor, heated spot all winter. It hesitates coming out of the hole shot then gets it's power back and takes off. Once it is running at speed it seems to have micro hesitations where I can just barely feel that it is not quite running as smoothly as it did at the end of last season. Almost like I am driving on rough water except that the water is glass.

It starts up fine and idles fine.

Any ideas? I changed out the fuel filter today but that did not fix it. Could the gas have gone bad? I haven't put any more in yet....maybe I'll try that monday AM. Anyways, any ideas and how to test them are appreciated. They fogged the cylinders...could that have screwed anything up like the injectors or the spark plugs?

Thanks

Bakes

Cap & rotor? Plugs?

It could be moisture in the fuel (condensation) or possibly a dirty injector.

yes gas could have gotten condensation and the cap and rotor may also have moisture in it.....try a new tank of gas.

Update....I pulled the cap and rotor off and they were corroded beyond belief. Quickly swapped them out and she is running great again

Nice! Good to hear!