1999 volvo 5.7 GL non efi stalls at idle whenever

New member here needeing advice please. Mechanic went away. I have a 1999 Four Winns with 211 original miles on everything but the new block and items replaced last month due to hydrolocking engine when aground. and over heated. NO alarm on this engine for that dry block situation and there is now a high block temp alarm installed by my mechanic. New engine purrs but old gas and electrical components are suspect in a stalling at idle when warming up mostly and even when at running temp at the dock only.

I have changed the filter twice (gas is shocked and sparkly clear).
I noticed a bad kink in the fuel pipe btwn Fuel Pump and Carb. I changed it with new factory one.
I checked the carb inlet filter and it is clear and clean.
I could not find a test kit to test the pump (only one on this model and low pressure 5 psi) with the right connecting fittings and simply ordered a new fuel pump and a new relay. (pump was $65 and Relay $23).

I am hoping I can fix this annoying condition and have my boat back after a year down.

Can anyone point me to the best method of changing this fuel pump in steps or on video? Also comment any ideas you may have or have encountered on this same condition and I would be very grateful. THX

pull the carb for a cleaning or open th idle mixture jets a bit more

Thank you Bt Doctur. I was told by my mechanic who is away for awhile that he only disassembled the old carb to the extent to replace the power valve and the needle and seat.
He replied this to me after I asked him why the butterfly valve was filthy and if he rebuilt the carburator. I have spray carb cleaner. Would it be okay to spray it in and clean it when it is running as the can states? I am clueless as why he did not simly clean and rebulild the carb.