evinrude won't stay running, 15 hp 1985

[DW]

I have a 1985 15 hp evinrude that used to run real good. the last time I took it out it started right up and ran about a mile wide open but when I let off the throttle it just quite and when I tried to restart it would start but only run 10 - 15 seconds. I had old gas 3 months old but since then I have bought a new gas tank and all new fule hoses and rebuilt the fule or vapor pump and took the carb a part and that looks good but cleaned it anyway. When I put some gas in the front of carb and pull 14 times it will start but it will knock and if I play with the throttle by the carb by hand I can keep it running so It will run but smells rich and smokes. It has a good spark also. any Ideas would be greatly appreciated. and thanks for your time. DW------------------D west

[ICEMAN]

Hi DW, One possibility is the fuel pump, A diaphram could be leaking internally. This can cause fuel to leak back thru the pulse hose, that operates the pump. This will cause that cylinder to run rich on fuel, flooding that cylinder. When the motor shut down, did it seem to be hot, if it was, I would pull the cylinder head and look at the cylinders and pistons, if they look OK, put a new head gasket in and run it, checking the temperature.