3.0 Mercruiser throttle problems

[Matt2104]

Hi, I am looking for any help or a pointer in the right direction, I have a 3.0 merceriser and all was fine last year, it run great, I have just pulled it out to put back in the water but now the thing is not running correctly, it starts and idles ok and if you give it a lot of gas it revs high but on low revs between 1000-2000rpm it just wants to die, I have changed the plugs, fuel pump and done a general service.
Is it likely to be the ignition system like the distributor or could it be the carb requires a rebuild? any pointers would be really appreciated.
Thanks

 

[QBhoy]

Bad fuel would be the odds on favourite.
But could be a range of other things. Was she winterised before winter ?

 

[spannerman]

I would suspect the carb, I get a few of these every season with carb problems usually due to water in sitting in the carb over winter. A strip down and clean sorts them out.