werdnaycart
New Member
I need some help with an overheating problem...I have a 2005 260 DA with 350 Mag MPI w/ bravo III. The engine is raw water cooled. I just had a new water pump (the entire pump not a rebuild) installed. The impeller had come apart, and there was bad scoring on the inside of the pump (which is why we replaced the whole thing) and we fished out all the old impeller pieces. The boat ran great for about 15 hours. Now this weekend, we put about 10 hours on the boat...drove about 100 miles round trip. Around hours 7-8 of our trip, the engine started increasing in temperature from 150-160ish up to about 185 over the course of 10 minutes. We were running around 3800-4000RPM when this happened. (we were in Pine Island Sound in FT. Myers, FL area) I then slowed to idle, and the temperature immediately spiked up to 200-210ish and alarm sounded. We shut down the engine lifted the hatch and all seemed normal (no leaks, belts were fine) checked the outdrive, no obvious blockage. After about 10-15 minutes we restarted the engine, and it cooled immediately down to 150-160 at idle (was around 185 when I turned the key). Ran at about 3800-4000RPM for about 10-15 minutes and began heating again slowly up to 185. Slowed to idle and immediately alarms went off and temp raised to 200ish, shut down motor waiting to cool, and restarted and again temp dropped and stayed steady at 155. This happened about 3-4 times over the course of an hour. Then for the last hour to 90 minutes of the trip, it did not reoccur. I noticed that while running at 3800-4000RPM the water pressure was up around 5 PSI. It seems to usually be in the 3-4 range. Manifolds and Risers on the boat are just under 2 years old. Most of the boating is done in fresh water (although not this day). The engine is always flushed with salt away after use. Any ideas on what could cause this? Thanks in advance everyone!
