I?m hoping to get some experience feedback.
I have a 1991 I/O OMC 4.3L with a cobra drive. The water temperature gauge seems to be running a little hotter than in recent years. The temp gauge is rock steady at engine idle (160-F) and runs up to 180-185 F at WOT.
Question #1. Should I be concerned about indicated WOT temp?
I purchased and installed both a water pump kit (sierra pn 18-3348) and thermostat kit (sierra 18-3653).
I did pull the water hose from the transom at the thermostat housing inlet to run the OMC manual outlined water pressure head test.
The engine speed at idle is ~ 750-800 rpm.
I hold the water hose level with the top of the spark arrester as outlined in the OMC manual.
I use a set of muffs and garden hose attached to the outdrive.
I see a pressure head of water at or slightly less than 2 inches.
Question #2. Do I have the correct setup to run this test?
I pulled the water pump housing and impeller from the outdrive.
I plugged my garden hose into the transom to thermostat housing hose at the thermostat housing and used a hose clamp to hold the garden hose in the transom to thermostat housing hose.
I turned the garden hose on and see water flowing freely from the discharge water pump port on the outdrive.
I re-installed the water pump housing without the impeller.
I turned the garden hose on and watch water flow freely and evenly from both water intake ports on the drive lower unit.
Observations/Conclusions.
I think the water flow from the water intake ports to the thermostat housing looks ok. I think I?m at the lower end of OMC manual defined press head at the thermostat housing inlet, provided I have the correct engine speed to run this test.
I?m thinking the indicated operating temp is at the thermostat open temperature and maybe the cooling capability is reduced at WOT. I?m thinking I need to look at exhaust leaks into the cooling water supply and the circulating pump and temperature sensor.
Any recommendations/thoughts or systemic problems with OMC cobra cooling systems?
I have a 1991 I/O OMC 4.3L with a cobra drive. The water temperature gauge seems to be running a little hotter than in recent years. The temp gauge is rock steady at engine idle (160-F) and runs up to 180-185 F at WOT.
Question #1. Should I be concerned about indicated WOT temp?
I purchased and installed both a water pump kit (sierra pn 18-3348) and thermostat kit (sierra 18-3653).
I did pull the water hose from the transom at the thermostat housing inlet to run the OMC manual outlined water pressure head test.
The engine speed at idle is ~ 750-800 rpm.
I hold the water hose level with the top of the spark arrester as outlined in the OMC manual.
I use a set of muffs and garden hose attached to the outdrive.
I see a pressure head of water at or slightly less than 2 inches.
Question #2. Do I have the correct setup to run this test?
I pulled the water pump housing and impeller from the outdrive.
I plugged my garden hose into the transom to thermostat housing hose at the thermostat housing and used a hose clamp to hold the garden hose in the transom to thermostat housing hose.
I turned the garden hose on and see water flowing freely from the discharge water pump port on the outdrive.
I re-installed the water pump housing without the impeller.
I turned the garden hose on and watch water flow freely and evenly from both water intake ports on the drive lower unit.
Observations/Conclusions.
I think the water flow from the water intake ports to the thermostat housing looks ok. I think I?m at the lower end of OMC manual defined press head at the thermostat housing inlet, provided I have the correct engine speed to run this test.
I?m thinking the indicated operating temp is at the thermostat open temperature and maybe the cooling capability is reduced at WOT. I?m thinking I need to look at exhaust leaks into the cooling water supply and the circulating pump and temperature sensor.
Any recommendations/thoughts or systemic problems with OMC cobra cooling systems?