Yamaha 250hp 2 Cycle - Bogging Down?

[jeff6645]

Looking for some help on solving a problem I am having with my 1993 Yamaha 250hp 2 cycle engine, thought someone on here may have had the same problem or knows what can cause it. I tried searching other sites and the answers ranged from trash the motor and start over to bad fuel.....

Here's what happing, it starts fine, idles find but when you give it fuel is starts out as normal then about 10 second later it start slowing down (bogging) sometimes to a idle sometimes just drops a few RPM. After a few minutes it clears up and runs fine. This is what I have tried, new gas/water separator filter (no water found in gas). New gas lines, removed an after market auto filter that was in line before the carburetors, new plugs. OEM bulb primer pump (old one had smaller entry & exit ports & was sucking flat). Seafoam, Deep Creep and another fuel product that they advertise on Sea Shape TV(can't remember the name).

When I pull the plugs they all look the same in color and wetness. I really think it's a fuel problem. If all else fail the next step is to rebuild the six carburetors. But if it is the carburetors wouldn't one or two plugs look different and the problem consistent?

Thank you for your suggestions.