07 Volvo Penta 5.0 GL stall issues at idle and wakeless speeds

[o7 Senza]

I have a 2007 Larson Senza 206 w/ VP 5.0 GL. I purchased the boat from a broker (as is deal) and it ran great for 2 tanks of gas. Third tank (all from the same station) filled up and now I have a stalling issue. It will not stay running unless I'm throttling it or keep the RPM's above 2200, any lower and it stalls. It also stalls at wakeless speeds unless I'm throttling it. It stalls while docking and recovering obviously...and my wife doesn't want to ride in it any longer. It pulls boarders out of the water with NO issue (as long as I throttle it) and at cruise or WOT, it drives great. ANY THOUGHTS???
I replaced the fuel/water filter; forgot to to pour and check for water. I have added fuel stabilizer.
Broker told me that it may be with the carb...some sort of electronic sensor???

[kenJ]

If you have a carb, it probably needs to be rebuilt. If fuel injected, run some injector cleaner through it. I would add it to the filter so it is a strong mix. I'm guessing the boat sat for a while. Boats do not like ethanol fuel, holds water, leaves deposits etc. If you can get gas without ethanol do it. If not make sure you add the stabilizer every time.