600 Fuel pump

[Bugs]

90FZR600. Long story short, was having a heck of a time running properly due to mis-matched carbs.

Local mechanic, very good with tuning working on the bike for me, as I'm over my head. Need some help still

The carbs were removed and a complete new Dyno-jet stage1 kit has been installed. Running the bike with HIS fuel tank/fuel pump my bike runs AWESOME.

As soon as he re installs my fuel tank and runs through my pump, the bike randomly dumps a pile of fuel in making it bog out and run terrible. Sometimes runs for a bit ok, but it eventually always does this fuel dump.

He is pretty much determined it needs a new fuel pump. So I have two questions:

1.) any other suggestions why this may be happening OTHER then the pump?
2.) which other fuel pumps will work on my bike? Are they interchangeable with other years or bikes? need some cross reference info.

Local shop has a used 97 yzf750 and one from a 2000 R6. hoping one of these would work.

PLEASE HELP