Recently replaced the long block on a 2006 Mercruiser MAG MPI 5.7L all was good in the beginning but recently I noticed that the engine struggles to plane and seems to gasp from a cold start. This behavior changes as soon as the engine is at 175 deg and after which the engine planes and has no issues running. Past this temp I could go back to 0 RPM and back on plane and it seems just run great.
Recently replaced the fuel plump regulator as the fuel pressure seemed to be too high. Compression checks were good on 7 cylinders. Number 8 was struggling to register but the scope looked good so we figured it maybe flooded with fuel due to the fuel regulator.
The engine starts just fine on cold starts and doesn't idle rough so I am not sure it’s the idle
Control valve. Mechanics I spoken to think it maybe an exhaust value job on 8. But I am not sure that explains the fact that once hot, the boat just runs ?
This is a 100% reproducible. Boat at 175 degrees is an absolute pleasure to ride and doesn’t seem to get hotter either.
Posting a video of what I sounds like cold when in gear.
Recently replaced the fuel plump regulator as the fuel pressure seemed to be too high. Compression checks were good on 7 cylinders. Number 8 was struggling to register but the scope looked good so we figured it maybe flooded with fuel due to the fuel regulator.
The engine starts just fine on cold starts and doesn't idle rough so I am not sure it’s the idle
Control valve. Mechanics I spoken to think it maybe an exhaust value job on 8. But I am not sure that explains the fact that once hot, the boat just runs ?
This is a 100% reproducible. Boat at 175 degrees is an absolute pleasure to ride and doesn’t seem to get hotter either.
Posting a video of what I sounds like cold when in gear.
