HELP 7.5 hp sears gamefisher

High I am a new member, I am working on a 7.5 gamefisfer, last year is ran ok and I was using the tank on top of the motor but the carb would start to leak gas when the motor was turned off so this year I put on a 2.5 gal tank, i got it running after about 1/2 hr but it would not idle and it would not run for more that a minute.

sounds like float valve sticking or carb float not working. Clean the carb and make sure the float is working. May be a piece of trahs hung in the float valve.

I will try cleaning out the carb, should i run with the tank on top or the 2.5 gal can. Would the fuel pump have anything to do with any of the problems ?, can i put a different carb on like one from a mower?

I had a 74 eska 5hp, I ordered a rebuild kit from ebay it was lik $20. I would not put a mower carb on it. It would lead to more troubles. I would use the tank on top, elimnate any issues with the remote tank ie, cracks or leaks in fittings or the hose itself. Mine wouldn't do good on the remote tank at alll. pump diaphram may need replacing. I replaced the "duck bil" diaphram on mine when I cleaned the carb etc. After I got my upper tank leak stopped it ran great. Also make sure your tank is rust free. You can get a kit from motorcycle shops made by kreem it cleans the rust by etching then you pour a rubber liquid in that coats the tank inside and solves all issues with a rusty tank