Southern Cross
Member
Hello everyone,
One of our engines is overheating and I'm at a loss. Boat is a 2005 320 with 350 V drives, closed cooling, 350hrs of fresh water use. It has an older smart craft but I don't think there are water pressure sensors or gauges.
Quick background, last weekend I ran into shallow water on the Potomac (2-3ft of silt bottom). Both engines and the generator overheated soon afterwards. I cleaned the sea strainers of some mud, oyster shell fragments, and some weeds. Engines remained hot (just under 175deg) but were pumping water with steam in the exhaust. I limped back to the dock on one engine at idle and did the following:
1. Drained the strainers and cleaned them again. Used Sea Flush kit and a shop vac to flush from the strainer to the thru hull.
2. Flushed the water hoses from the strainer to the water pumps
3. Replaced the raw water pump impellers on both engines as well as the generator. (all looked fine, no cracks or missing vanes but replaced with new anyway)
4. Removed all raw rater hoses and the end caps on the heat exchanger and flushed with a hose. No major debris came out.
5. Flushed both engines with the dock hose and the engine's fresh water flush system.
The generator and starboard engine now run great. The starboard engine exhaust expels water strongly with increasing force as I increase throttle. Both manifold elbows are warm but not hot and the temp gauge reads normal.
The problem remains with the port engine. The water coming out of the exhaust is does not come out forcefully like the starboard side and the inboard elbow is much hotter than the outboard one or the ones on the starboard engine
I rechecked all hoses by disconnecting them...it looks like water is pumping strong through the hoses and heat exchanger.
A few possibilities I've considered:
1. Is it possible for a raw water pump with a good impeller and proper belt tension to not pump enough water? I've only ever had them fail completely.
2. Could the elbow or riser be clogged? I'm at a loss for how something could make it all the way though the strainer, transmission cooler, and heater exchanger and then clog a riser.
3. Thermostat? The problem seems to be with the raw water side of things--do the two systems interact in any way that this could be the problem?
I stopped short of pulling the elbow off tonight because it was hot and I have never done that before--frankly I don't even know what I would be looking for and was concerned about needing a gasket if I took it off.
Curious if anyone else has experienced something similar or can think of something I am missing. Thanks in advance, I am looking forward to the discussion.
One of our engines is overheating and I'm at a loss. Boat is a 2005 320 with 350 V drives, closed cooling, 350hrs of fresh water use. It has an older smart craft but I don't think there are water pressure sensors or gauges.
Quick background, last weekend I ran into shallow water on the Potomac (2-3ft of silt bottom). Both engines and the generator overheated soon afterwards. I cleaned the sea strainers of some mud, oyster shell fragments, and some weeds. Engines remained hot (just under 175deg) but were pumping water with steam in the exhaust. I limped back to the dock on one engine at idle and did the following:
1. Drained the strainers and cleaned them again. Used Sea Flush kit and a shop vac to flush from the strainer to the thru hull.
2. Flushed the water hoses from the strainer to the water pumps
3. Replaced the raw water pump impellers on both engines as well as the generator. (all looked fine, no cracks or missing vanes but replaced with new anyway)
4. Removed all raw rater hoses and the end caps on the heat exchanger and flushed with a hose. No major debris came out.
5. Flushed both engines with the dock hose and the engine's fresh water flush system.
The generator and starboard engine now run great. The starboard engine exhaust expels water strongly with increasing force as I increase throttle. Both manifold elbows are warm but not hot and the temp gauge reads normal.
The problem remains with the port engine. The water coming out of the exhaust is does not come out forcefully like the starboard side and the inboard elbow is much hotter than the outboard one or the ones on the starboard engine
I rechecked all hoses by disconnecting them...it looks like water is pumping strong through the hoses and heat exchanger.
A few possibilities I've considered:
1. Is it possible for a raw water pump with a good impeller and proper belt tension to not pump enough water? I've only ever had them fail completely.
2. Could the elbow or riser be clogged? I'm at a loss for how something could make it all the way though the strainer, transmission cooler, and heater exchanger and then clog a riser.
3. Thermostat? The problem seems to be with the raw water side of things--do the two systems interact in any way that this could be the problem?
I stopped short of pulling the elbow off tonight because it was hot and I have never done that before--frankly I don't even know what I would be looking for and was concerned about needing a gasket if I took it off.
Curious if anyone else has experienced something similar or can think of something I am missing. Thanks in advance, I am looking forward to the discussion.