I have a 1996 mercury 150 blackmax XRI EFI that ran great, till it all of the sudden wouldn't get over 1000 rpm's I can give it gas and it's like it's just bogging down, I have replaced the water separator filter, the plugs, and primer bulb and half of the feul line, when it started this it would do it for about an hour then run fine for a while then do it again, now it just does it all the time, any help would be greatly appreciated