Late model A/S boats from 1996-2002 are all EFI engines, the majority are TBI (Throttle Body Injection) with a few equipped with MPI (Multi Port Injection) the following is for all TBI owners:
TBI systems are very reliable but when they act up you must be very careful in your diagnosis and part replacement. An auto parts store may think that a 1995 chevy pickup w/ 5.7 engine TBI injectors will work, and it does look the same, fits right in the bowl & starts but wait, the engine is not running right??? Well that injector is designed to operate at 9-13psi line pressure, but your boat is delivering 32-35psi, essentially doubling the fuel into the engine! Unlike the auto industry where they set a production run of hundreds of thousands of cars or trucks with the same calibration, the marine industry deals in hundreds period. In the Marine Power TBI series there are (2) basic HP configurations 275 & 315, fuel pressure for most at 32-35psi, some at 9-13 as the variables begin to multiply so does the confusion. The ECM (engine computer) is programmed to pulse the injectors & takes into account the fuel line pressure, the regulator spring, and the injector size to optimize performance. Too much fuel & you foul plugs, run rough, waste fuel, too lean & the engine runs great for a short while then literally melts pistons.
Bottom Line: These parts are becoming more difficult to find, and much more difficult to decipher, I am collecting data & working with Marine Power to offer continued support for these engines. Call or email before servicing, please. 985-542-4336
