Fuel squirting everywhere

Hi all, I'm new to the forum and really glad I've found you! Very excited about finally owning a Triumph just bought a 1997 T509 885cc black Speed Triple! Had a few great runs out on it and I love it, but it developed a stalling habit at the traffic lights/ junctions etc. Feels a bit 'fluffy' in low revs. So in my wisdom I'm doing some basic servicing (I can't faff with injection system or anything too technical) but I've changed to iridium plugs: the tops of the plugs are different to the standards I removed, no little threaded tip, but seemed to fit inside the springs in connectors ok, is that right? Then I fitted a new K&N air filter, relatively easily. Then a new fuel pump after not draining tank and sploshing fuel everywhere however.... having refitted all hoses and wires, when I turn on ignition there is fuel squirting from the fuel hose connectors on the side as it primes. I'll add that I ordered new o ring seals but the ones sent were too thick so I reused the originals...is that the problem? Poor seal or is the fuel pressure too high? Has anyone experienced this problem? Any advice please, I'm gutted my lush bike is off the road!