"My 2002 5.0 GL has developed
"My 2002 5.0 GL has developed an overheating problem. Two months ago I had the raw water pump impeller replaced as normal maintenance. Boat ran fine before impeller work with no signs of overheating. I did not get to run the boat after the impeller replacement and had to leave the country for two months. Now first trip out and it overheated a few minutes after starting. I have (carefully) loosened the raw water discharge hose with the engine idling and a good stream of water comes out so it seems the raw water pump is working OK. The boat is on an over-water hoist so I have checked the water discharge from the stern drive exhaust ports while the water intake is submerged. There is no water discharge while the engine is running, but there is a normal discharge from the exhaust ports if I run water from a garden hose to the engine flushing connection. The first flush water that comes out does have what appears to be fine black solids in it.
In reading other posts I gather the exhaust manifold water passages could be clogged. The boat is run in salt water (Galveston Bay) and the manifolds have not been replaced or boiled out. However, the discharge of flush water and the fact that both sides have suddenly stopped gives me hope that perhaps the problem may just be a stuck thermostat. Would a stuck thermostat give this kind of symptoms? I have not pulled the thermostat housing yet so I am not sure what the water flow arrangement is.
Have out of town guests coming in for fishing over the Memorial Day weekend, so I would appreciate troubleshooting assistance and hopefully quick fix ideas.
Thanks for the help."
"My 2002 5.0 GL has developed an overheating problem. Two months ago I had the raw water pump impeller replaced as normal maintenance. Boat ran fine before impeller work with no signs of overheating. I did not get to run the boat after the impeller replacement and had to leave the country for two months. Now first trip out and it overheated a few minutes after starting. I have (carefully) loosened the raw water discharge hose with the engine idling and a good stream of water comes out so it seems the raw water pump is working OK. The boat is on an over-water hoist so I have checked the water discharge from the stern drive exhaust ports while the water intake is submerged. There is no water discharge while the engine is running, but there is a normal discharge from the exhaust ports if I run water from a garden hose to the engine flushing connection. The first flush water that comes out does have what appears to be fine black solids in it.
In reading other posts I gather the exhaust manifold water passages could be clogged. The boat is run in salt water (Galveston Bay) and the manifolds have not been replaced or boiled out. However, the discharge of flush water and the fact that both sides have suddenly stopped gives me hope that perhaps the problem may just be a stuck thermostat. Would a stuck thermostat give this kind of symptoms? I have not pulled the thermostat housing yet so I am not sure what the water flow arrangement is.
Have out of town guests coming in for fishing over the Memorial Day weekend, so I would appreciate troubleshooting assistance and hopefully quick fix ideas.
Thanks for the help."