3.0 mercruiser w/alpha 1 engine sputters when shutting off

I have a 2000 mercruiser 3.0 2bbl carb. that when I try and shut it off, it sputters and then after a few sputters it will finally shut off. Its had all scheduled maintenance, and have had this problem since about the 2nd year, its got new spark plugs etc. Any similar experiences would be appreciated. It starts up fine, will run fine at idle and low speeds, but when i give it more throttle it bogs for a few seconds, then will open up. I have heard about the inline fuel filter on the carb, and will be looking at that this week, but wondered if anything else i should be looking for.

 

The throttle and idle mixture are out of adjustment. It may also need to be rebuilt.

 

ok, it doesnt do it everytime i shut it off, only about half the time....I dont know if that would make a difference or not.

 

Also once it is warmed up it runs perfect, but it starts up hard and runs rough, I let it idle for a few minutes when i first start it in the water, i take off from the launch slow, and then once i drop the throttle down it bogs, and then after a short stutter will start to take off. I am trying to get this back to when i started it for the first time.

 

Yes, check the fuel filter. I agree with Gonzo, it sounds like your carb's idle jets are not set properly for the conditions you use this boat in. A bit of on-the-water carb tuning is in order for sure. Hopefully you don't need a rebuild on a 6-year-old carb, but it's quite possible that you do.