BrianAmberjack
New Member
- Jul 19, 2021
- 13
- Boat Info
- 1989 Sea Ray 270 Amberjack
- Engines
- 4.4L Mercruiser Alpha I X 2
Good Day Club Sea Ray Skippers. As the title of this thread indicates, I am having a problem with one of my engines. I apologize for long thread intro, and I will try to use point form as much as I can to mitigate that. I have been searching through as many forums as I can in order to resolve the engine problem, and only now, after an entire season of troubleshooting and testing, have I come to the point of having to ask for help directly from the Club Sea Ray community.
Please read the entirety of what I have already done, before making suggestions.
The Boat: 1989 Sea Ray 270 Amberjack, twin 4.3LX mercruiser engines(according to the purple aluminum tag on the carbs), Thunderbolt Ignition, Rochester 4 barrel carbs, water separating fuel-filters, anti-syphon valve on port supply line, separate fuel tanks, only ever seen fresh water in Lake Ontario. Props in great shape.
My History:
Avionic Tech from Canadian Armed Forces,
have rebuilt auto engines, replaced auto engines,
rebuilt/installed Volvo-Penta MD2B diesel system in home-built C&C 36R sail boat hull, still running great
usually do all of my own vehicle maintenance/repairs, am a newb to out-drives and marine gas engines
Operational History:
May 2021 - purchased boat, ran perfectly all season
June 2022 - ran fine but Port Outdrive impellor failed,
drained and pulled lower section,
replaced impellor,
replaced outdrive lube oil, incorrect procedure, did not put enough oil in drive
was under the impression that the out-drive had an oil pump,
assumed that the oil would be circulated through-out the drive sections, not all settling to lower unit
Stupid-Stupid-Stupid, at the end of the season (had a great season moving the Boat along the North Shore of Lake Ontario, then up the Trent Severn Waterway to Lake Simcoe Ontario) while at 4200rpm and on plane, the port outdrive began to seize, the engine slowed, I shut it down, a single back-fire, done
Sept/Oct 2022 - Broke down port outdrive, flushed lower unit clean, located/purchased/installed used matching (gear ratio) upper unit, new gasket kit, reinstalled to boat. Winterized both engines
May 2023 - flushed winterizing anti-freeze out of engines while running on trailer with muffs, engines warmed up/idled/revved well, launched at dock in Lake Simcoe and headed out, 5 min out Port engine stalls, continued on starboard engine to new marina.
The Symptoms: Fairly quickly discovered that the fuel filters both contained water, drained them both, cleaned the water out of the port carb bowl, she started right up (after the expected turn-over time to get the fuel into the carb), replaced both fuel filters with glass bowl type for easier and more frequent inspection (newb mistake, not flushing them out and regularly inspecting for water. Never had this issue with the sail boat diesel system), during sea trial she started perfectly, ran smoothly, idled out of marina as expected, pushed the throttles up, rpm/power increased, noticed prt throttle getting ahead of strbd throttle, port rpm/power topped out at 2800rpm, strbd was able to go up past 4k. and that is how it was all season
The Repair: Following the advice of many people, an auto-mechanic buddy, and forums, this is what I have done, not necessarily in this order
Fuel System -
completely drained the port fuel tank (there was a lot of water present),
inspected riser tube,
inspected vent hose,
inspected fuel input hose,
ran vacuum into fuel inlet hose,
determined all fuel/air paths to be unobstructed and free of debris,
filled tank with new fuel,
removed anti-syphon valve from prt fuel feed line,
replaced fuel filter/cannister,
disconnected and blew out fuel to fuel-pump line, no obstructions
removed and inspected prt fuel-pump, found no fault,
exchanged prt and strbd fuel-pumps,
disconnected and blew out steel high-pressure fuel-pump to carb line, no obstructions
broke down carb,
replaced screen filter, accelerator pump, valve bearing, all gaskets (in other words a carb rebuild), but found no issues other than corrosion resulting from the water in the bowl chambers
exchanged prt and strbd carbs
Air System -
inspected, cleaned, then exchanged both flame arrestors
attempted a vacuum leak test using an unignited propane torch (no flame, just gas) around all of the air intake carb and manifold gasket joints, yielded no results, but when I tried dumping directly into the carb had no resulting increase in rpm either, so this may be something worth retrying with some ether/starting spray. as the symptom still seems like loss of vacuum to me
Control System -
measured throttle arm displacement and throttle butterfly movement of both engines. When the throttles are pushed forward to 50%, the throttle valves open to exactly the same positions
Ignition System -
replaced spark plugs, gapped to .035", old ones showed evidence of extreme lean fuel,
replaced ignition wires,
inspected rotor, a bit old but comparable to strbd rotor,
exchanged prt and strbd rotors,
exchanged prt and strbd distributer caps,
exchanged prt and strbd rotor position sensors,
exchanged prt and strbd "ignition amplifiers", although I think that what this actually does is replace the points, and control ignition timing and advance the timing as rpm increases,
checked ignition timing, port was 14 DBTDC, strbd was at 10 DBTDC, plenty of spark produced by coil,
adjusted both to 8 DBTDC according to the shop manual, both engines running very 'smoothly",
checked for ignition timing advance with rpm increase, timing advances to 12DBTDC at 2k rpm (if I recall correctly)
exchanged prt and strbd ignition coils,
Engine System -
checked compression on both engines, cold
Strbd cylinders were all 148-150 psi, no leak down test conducted
Prt cylinders were all 148-149 psi, no leak down test conducted
the manual says that the compression pressure of the 4.3l LX engine cylinders should be 180 psi, since both engines are comparable I moved on
Oil level of both engines was between the max and min lines on the dip stick, and had been changed every year
After each addition/change/adjustment, the boat was taken out and no change was observed, other than they both ran a bit smoother (probably the ignition timing adjustment). Starboard still awesome, port still starving for power.
She is out of the water and winterized now. Next spring my plan is to exchange the outdrives. They have been removed and the lube oil changed. Oil was free of filings, water, or any other contaminants. I shoved a borescope up the exhaust path to inspect for flapper obstruction. No obstruction was observed. Still a chance that the flapper/s are obstructing but not disconnected. May have to remove the engine side exhaust from manifold.
I have a couple more ideas, then I'm out. Any help would be appreciated
Please read the entirety of what I have already done, before making suggestions.
The Boat: 1989 Sea Ray 270 Amberjack, twin 4.3LX mercruiser engines(according to the purple aluminum tag on the carbs), Thunderbolt Ignition, Rochester 4 barrel carbs, water separating fuel-filters, anti-syphon valve on port supply line, separate fuel tanks, only ever seen fresh water in Lake Ontario. Props in great shape.
My History:
Avionic Tech from Canadian Armed Forces,
have rebuilt auto engines, replaced auto engines,
rebuilt/installed Volvo-Penta MD2B diesel system in home-built C&C 36R sail boat hull, still running great
usually do all of my own vehicle maintenance/repairs, am a newb to out-drives and marine gas engines
Operational History:
May 2021 - purchased boat, ran perfectly all season
June 2022 - ran fine but Port Outdrive impellor failed,
drained and pulled lower section,
replaced impellor,
replaced outdrive lube oil, incorrect procedure, did not put enough oil in drive
was under the impression that the out-drive had an oil pump,
assumed that the oil would be circulated through-out the drive sections, not all settling to lower unit
Stupid-Stupid-Stupid, at the end of the season (had a great season moving the Boat along the North Shore of Lake Ontario, then up the Trent Severn Waterway to Lake Simcoe Ontario) while at 4200rpm and on plane, the port outdrive began to seize, the engine slowed, I shut it down, a single back-fire, done
Sept/Oct 2022 - Broke down port outdrive, flushed lower unit clean, located/purchased/installed used matching (gear ratio) upper unit, new gasket kit, reinstalled to boat. Winterized both engines
May 2023 - flushed winterizing anti-freeze out of engines while running on trailer with muffs, engines warmed up/idled/revved well, launched at dock in Lake Simcoe and headed out, 5 min out Port engine stalls, continued on starboard engine to new marina.
The Symptoms: Fairly quickly discovered that the fuel filters both contained water, drained them both, cleaned the water out of the port carb bowl, she started right up (after the expected turn-over time to get the fuel into the carb), replaced both fuel filters with glass bowl type for easier and more frequent inspection (newb mistake, not flushing them out and regularly inspecting for water. Never had this issue with the sail boat diesel system), during sea trial she started perfectly, ran smoothly, idled out of marina as expected, pushed the throttles up, rpm/power increased, noticed prt throttle getting ahead of strbd throttle, port rpm/power topped out at 2800rpm, strbd was able to go up past 4k. and that is how it was all season
The Repair: Following the advice of many people, an auto-mechanic buddy, and forums, this is what I have done, not necessarily in this order
Fuel System -
completely drained the port fuel tank (there was a lot of water present),
inspected riser tube,
inspected vent hose,
inspected fuel input hose,
ran vacuum into fuel inlet hose,
determined all fuel/air paths to be unobstructed and free of debris,
filled tank with new fuel,
removed anti-syphon valve from prt fuel feed line,
replaced fuel filter/cannister,
disconnected and blew out fuel to fuel-pump line, no obstructions
removed and inspected prt fuel-pump, found no fault,
exchanged prt and strbd fuel-pumps,
disconnected and blew out steel high-pressure fuel-pump to carb line, no obstructions
broke down carb,
replaced screen filter, accelerator pump, valve bearing, all gaskets (in other words a carb rebuild), but found no issues other than corrosion resulting from the water in the bowl chambers
exchanged prt and strbd carbs
Air System -
inspected, cleaned, then exchanged both flame arrestors
attempted a vacuum leak test using an unignited propane torch (no flame, just gas) around all of the air intake carb and manifold gasket joints, yielded no results, but when I tried dumping directly into the carb had no resulting increase in rpm either, so this may be something worth retrying with some ether/starting spray. as the symptom still seems like loss of vacuum to me
Control System -
measured throttle arm displacement and throttle butterfly movement of both engines. When the throttles are pushed forward to 50%, the throttle valves open to exactly the same positions
Ignition System -
replaced spark plugs, gapped to .035", old ones showed evidence of extreme lean fuel,
replaced ignition wires,
inspected rotor, a bit old but comparable to strbd rotor,
exchanged prt and strbd rotors,
exchanged prt and strbd distributer caps,
exchanged prt and strbd rotor position sensors,
exchanged prt and strbd "ignition amplifiers", although I think that what this actually does is replace the points, and control ignition timing and advance the timing as rpm increases,
checked ignition timing, port was 14 DBTDC, strbd was at 10 DBTDC, plenty of spark produced by coil,
adjusted both to 8 DBTDC according to the shop manual, both engines running very 'smoothly",
checked for ignition timing advance with rpm increase, timing advances to 12DBTDC at 2k rpm (if I recall correctly)
exchanged prt and strbd ignition coils,
Engine System -
checked compression on both engines, cold
Strbd cylinders were all 148-150 psi, no leak down test conducted
Prt cylinders were all 148-149 psi, no leak down test conducted
the manual says that the compression pressure of the 4.3l LX engine cylinders should be 180 psi, since both engines are comparable I moved on
Oil level of both engines was between the max and min lines on the dip stick, and had been changed every year
After each addition/change/adjustment, the boat was taken out and no change was observed, other than they both ran a bit smoother (probably the ignition timing adjustment). Starboard still awesome, port still starving for power.
She is out of the water and winterized now. Next spring my plan is to exchange the outdrives. They have been removed and the lube oil changed. Oil was free of filings, water, or any other contaminants. I shoved a borescope up the exhaust path to inspect for flapper obstruction. No obstruction was observed. Still a chance that the flapper/s are obstructing but not disconnected. May have to remove the engine side exhaust from manifold.
I have a couple more ideas, then I'm out. Any help would be appreciated
.........if it was running without a problem until the drive failed and rebuilding the drive/re installing it.......led to a performance problem.....I don't believe that is a coincidence. 