1996 250 TURU fuel prob?

I have a '96 250 saltwater series 2 and am having trouble with it at wot. It starts fine and idles fine. Its when it gets to 5000 rpms it starts to bog down and drop back down to 4300-4500rpms. The motor has been sitting for a couple of months so i am thinking its a carb prob so to try and avoid a carb tear down i did a shock treatment with seafoam. yesterday i took it out and it was still doing it, i noticed everytime it would start to bog down the fuel filter on the outboard would suddenly get bubbles in it, however i took a spare fuel tank and line and hooked it up and it ran near perfect. Is this a anti-siphon valve issue or a cracked fuel line somewhere. any insight would be great. its on a grady white 247 strike.

thanks

[jb123]

air leak from tank to motor filter, replace fuel lines, ball and check all connections, including separator seat

will do, thanks