hello everyone. So I have a 2006 Mercury 50hp EFI 4 stroke on a triton 1756SC that was running great and then went into storage for almost a year without running. Prior to storage we did add fuel stabilizer and topped off the tank.
Basically the engine runs fine now after everything I’ve done. But it still doesn’t have any power or reaching RPMs above 4K while in the water? Below are my notes, sorry for the long post but I figured more information is better.
2006 Mercury 50Hp EFI
Model: 1A51412FZ
Serial: 1C027993
Throttle cable: 84-896536A01
Boat running very sluggish after sitting in storage.
Drained fuel, replaced with 93 octane
Added cleaner/stabilizer (Star Tron -Enzyme cleaner)
Test run #1
Ran approximately 3 hours (18mph)
Replaced plugs, gapped at .040
Added more fuel and another pint of cleaner
Test run #2
Ran approximately 2 hours (14mph)
Replaced High pressure fuel pump
Replaced HPFP screen
Cleaned Vapor separator tank
Cleaned needle in VST
Test run #3
Ran approximately 1 hour - better but sluggish (23mph). Doesn’t seem to open up and reach 5600rpm.
Removed and cleaned fuel injectors
Dropped off at FC marina for diagnosing: no PC or diagnostic done expect fuel pressure gauge.
Fuel pressure reading 150!?
Picked up boat, ordered fuel regulator for VST.
Removed, drained VST again (no debris), installed new pressure regulator
Verified 42psi at shader on VST.
Engine revs with fast idle with muffs,
Test run #4 (30 minutes)
still sluggish in water, no rpm acceleration past half throttle.
Found 20amp fuse blown off ECM - replaced fuse
Before fuse replacement:
At idle: 52Hz
At full fast idle 175Hz
After fuse replacement:
At idle: 70Hz
At full fast idle 620Hz
In gear .... 620 and wasn’t full open...
Checked all fluids, topped off lower gear oil. Regressed transmission shaft & steering tube.
Test run #5 (45 minutes)
Motor failed to start but would eventually start and run at idle. Weather was cool but not cold (approx 60 degrees). After a 5 minute idle, ran continuously but did not sound smooth randomly.
Follow up on voltage regulator fuse;
After test run, checked the fuse at the launch just after pulling boat from the water. Holder was hot and fuse shows signs of excessive heat. Fuse was not blown. Ordered new voltage regulator, Tachometer and voltage gauge.
Spark plugs 1&2 look a bit burnt after less than 6 hours. Plug 3 looks barely used. 4 shows high heat also.
Suspect coil. Pulled coils 2&3 to compare. No cracks. Pulled all 4 coils and Followed Mercury bulletin No. 2008-09 for ignition coils harness service. All coils tested exactly the same for ohms/continuity tests and well within ranges of specified bulletin.
Verified ohms for spark plug leads. 8” leads read .739 k scale, no cracks, worn or burnt spots.
Replaced all 4 spark plugs with normal Champion RA8HC gapped at 040.
Swapped 2&3 coils&leads.
Replaced voltage regulator
3 beep warning and low battery
Charged battery
Ran in driveway with muffs. Sounds smoother. Idle no load approx 875rpm
Filled fuel tank
Test run #6. 2 people (approx 1 hour)
Started fine, rpm around 900 in N
Idle in gear sounded rough rpm a little lower maybe 850 range. Cooling spray a little weak at idle
1100 rpm engine smoothed out
Cooling spray looks good at 1100
Full open throttle still only reaching 3000, still sounds bogged down. 1 person on bow to help plane boat rpm reached 3800 going up river @ 16mph
Swapped props as a test. Smaller original engine prop installed. Max 3200 max rpm. Smaller prop should have less resistance equal to higher rpm.
Fast idle will reach almost 6k rpm??
Basically the engine runs fine now after everything I’ve done. But it still doesn’t have any power or reaching RPMs above 4K while in the water? Below are my notes, sorry for the long post but I figured more information is better.
2006 Mercury 50Hp EFI
Model: 1A51412FZ
Serial: 1C027993
Throttle cable: 84-896536A01
Boat running very sluggish after sitting in storage.
Drained fuel, replaced with 93 octane
Added cleaner/stabilizer (Star Tron -Enzyme cleaner)
Test run #1
Ran approximately 3 hours (18mph)
Replaced plugs, gapped at .040
Added more fuel and another pint of cleaner
Test run #2
Ran approximately 2 hours (14mph)
Replaced High pressure fuel pump
Replaced HPFP screen
Cleaned Vapor separator tank
Cleaned needle in VST
Test run #3
Ran approximately 1 hour - better but sluggish (23mph). Doesn’t seem to open up and reach 5600rpm.
Removed and cleaned fuel injectors
Dropped off at FC marina for diagnosing: no PC or diagnostic done expect fuel pressure gauge.
Fuel pressure reading 150!?
Picked up boat, ordered fuel regulator for VST.
Removed, drained VST again (no debris), installed new pressure regulator
Verified 42psi at shader on VST.
Engine revs with fast idle with muffs,
Test run #4 (30 minutes)
still sluggish in water, no rpm acceleration past half throttle.
Found 20amp fuse blown off ECM - replaced fuse
Before fuse replacement:
At idle: 52Hz
At full fast idle 175Hz
After fuse replacement:
At idle: 70Hz
At full fast idle 620Hz
In gear .... 620 and wasn’t full open...
Checked all fluids, topped off lower gear oil. Regressed transmission shaft & steering tube.
Test run #5 (45 minutes)
Motor failed to start but would eventually start and run at idle. Weather was cool but not cold (approx 60 degrees). After a 5 minute idle, ran continuously but did not sound smooth randomly.
Follow up on voltage regulator fuse;
After test run, checked the fuse at the launch just after pulling boat from the water. Holder was hot and fuse shows signs of excessive heat. Fuse was not blown. Ordered new voltage regulator, Tachometer and voltage gauge.
Spark plugs 1&2 look a bit burnt after less than 6 hours. Plug 3 looks barely used. 4 shows high heat also.
Suspect coil. Pulled coils 2&3 to compare. No cracks. Pulled all 4 coils and Followed Mercury bulletin No. 2008-09 for ignition coils harness service. All coils tested exactly the same for ohms/continuity tests and well within ranges of specified bulletin.
Verified ohms for spark plug leads. 8” leads read .739 k scale, no cracks, worn or burnt spots.
Replaced all 4 spark plugs with normal Champion RA8HC gapped at 040.
Swapped 2&3 coils&leads.
Replaced voltage regulator
3 beep warning and low battery
Charged battery
Ran in driveway with muffs. Sounds smoother. Idle no load approx 875rpm
Filled fuel tank
Test run #6. 2 people (approx 1 hour)
Started fine, rpm around 900 in N
Idle in gear sounded rough rpm a little lower maybe 850 range. Cooling spray a little weak at idle
1100 rpm engine smoothed out
Cooling spray looks good at 1100
Full open throttle still only reaching 3000, still sounds bogged down. 1 person on bow to help plane boat rpm reached 3800 going up river @ 16mph
Swapped props as a test. Smaller original engine prop installed. Max 3200 max rpm. Smaller prop should have less resistance equal to higher rpm.
Fast idle will reach almost 6k rpm??