1988 4hp, quits, need help, advice

[GoldToyBox]

I'm far from an expert on outboards. My 4hp Yamaha starts on the first pull when choked, then dies, unchoke it and it fires up. Now the problem, it runs for about 15 minutes at *****ing speed (less at full throudle). Seems to be running out of fuel. It will not restart without waiting for approx an hour. Removed Carb, disassembled found nothing wrong & clean. Cleaned and reassebled but still have the same problem. New plug and new fuel. Fuel flows fine from tank.
What is my next move?
Carb kit?
Sure seems to be running out of fuel, needle & seat, float all look ok but I don't know what the diaphrams should look like?
Any help and/or advice welcome

[Ken]

GTB,
Make sure the vent on the gas tank is open and not clogged up - when the motor dies, squeeze the fuel line bulb to see if it is still hard.
Good luck,
Ken K

[GoldToyBox]

In reply to:
"Make sure the vent on the gas tank is open and not clogged up - when the motor dies, squeeze the fuel line bulb to see if it is still hard"

Fuel is gravety feed (checked flow to carb ok) and the vent is open (even opened cap to be sure).

I'm going to order the carb kit and see what happens.
I bought this motor used about 4 years ago and it's run great (lots of hours, I live next to two lakes) only thing I've ever done is replace the plug last year. What is the correct plug gap? Nkg 4322 BR8HS
Any other thoughts?
Thanks for any input