Our boat has twin V8 Volvo Penta 5.0L GXI-B DP engines, S/N 4012062128 (Port) and S/N 4012062153 (Starboard). The boat's a 2002; we bought it in August 2007. We stored her on land for the winter, paying the boat yard to winterize and summerize. We launched on April 26th; on the way back to the marina, an audible alert went off in the engine compartment. The oil pressure, and water temp were fine, so, after checking the engines for something obvious, we proceeded to the marina (only a couple of miles from the boat ramp).
After closer inspection, I discovered the wire was off of the port engine outboard exhaust riser sensor, so I reconnected it and went for a test cruise. I idled out of the marina without the alarm sounding, but after about 30 seconds on plane the beeping started again. I immediately turned around and headed back in. Once back at idle, shutting-down and re-starting the port engine silences the alarm. I've changed both sea-water impellers and both thermostats; the only visible sign of trouble was a couple of missing impeller blades on the STARBOARD engine. I notice that the port engine gets up to temperature a little quicker than the starboard engine, but this may have been happening all the time and I just didn't notice. I was told that the engine with the power-steering pump will come up to temp a little faster than the other one, but I just didn't pay that close attention last season. I took her out after changing the sea-water pump impellers (no change) and again after changing the thermostats (again, no change).
I called my local boat dealer (where I purchased the parts) and the Service Manager suggested that, since the oil pressure/levels are good and I'm not exceeding 160 degrees (thermostat temp) when the alarm sounds, I should disconnect both exhaust riser temp sensors. He says they were problematic and have been discontinued on replacement risers. This makes me nervous. My instinct says to replace the sensors, but if they are worthless anyway, and have been discontinued, what would be the point? I've been too cautious to continue on plane to see if the engine temps even out, or if the port engine water temp continues to climb. What do you suggest?
After closer inspection, I discovered the wire was off of the port engine outboard exhaust riser sensor, so I reconnected it and went for a test cruise. I idled out of the marina without the alarm sounding, but after about 30 seconds on plane the beeping started again. I immediately turned around and headed back in. Once back at idle, shutting-down and re-starting the port engine silences the alarm. I've changed both sea-water impellers and both thermostats; the only visible sign of trouble was a couple of missing impeller blades on the STARBOARD engine. I notice that the port engine gets up to temperature a little quicker than the starboard engine, but this may have been happening all the time and I just didn't notice. I was told that the engine with the power-steering pump will come up to temp a little faster than the other one, but I just didn't pay that close attention last season. I took her out after changing the sea-water pump impellers (no change) and again after changing the thermostats (again, no change).
I called my local boat dealer (where I purchased the parts) and the Service Manager suggested that, since the oil pressure/levels are good and I'm not exceeding 160 degrees (thermostat temp) when the alarm sounds, I should disconnect both exhaust riser temp sensors. He says they were problematic and have been discontinued on replacement risers. This makes me nervous. My instinct says to replace the sensors, but if they are worthless anyway, and have been discontinued, what would be the point? I've been too cautious to continue on plane to see if the engine temps even out, or if the port engine water temp continues to climb. What do you suggest?
