I have a 2001 Mercury, 225 EFI that recently had a new powerhead installed. It ran great until it blew. Now, when I try to get on plane, it spits and sputters, but slowly gets on plane. Once on plane, it runs great, can stop and it gets on plane fairly well again. But if I idle for a couple minutes, it sputters and spits again. Have changed spark plugs, but no help. Could I have dirty or bad injectors? I have noticed that the fuel pump takes about 20 seconds to pressurize, (now six years old). Any help will be greatly appreciated.
