Seahorse and Company...

Prefishing for tournament i smelled gas and my engine died.. Took off top cap and got engine started and notice a huge gas leak in this 'thing' in the gas line that looks like a 'T' valve (metal) that has a thread on one of the 3 ends with a bicycle cap looking thing. The leak was not the cap.. but a leak in the seam between the bronze fitting and the T valve metal housing.

I used this gas tank emergency puddy stuff and wrapped with emergency tape and it it sealed totally and got me through the 2 day tournament.

Questions..

1. what is the function of this valve ?
2. any harm to my engine leaving my jerry fix on ?
3. my mechanic tells me that to get that piece fixed i need to buy an entirely new fuel line harness assembly that is like 250 bucks just for the part !

Any help on this ?

Thanks