Hello,
I'm new to the forum and somewhat of a new boat owner (3rd year), so I apologize in advance if this post doesn't follow the rules or my logic is flawed.
I own a 2002 190 Wellcraft Excalibur Sport Platinum with a Volvo Penta 3.0GSP-C engine. After running for 5 minutes @ ~1,500-2000 rpm (or higher) a repeating alarm sound occurs. When I disconnect the wire attached to "Thermo monitor, coolant temp. 872066" (https://www.marinepartseurope.com/e...ts.aspx?Catalog=7744380&Category=30&View=9453), the alarm stops. The temperature on the temperature gauge reads ~175F, which seems to be within the normal operating range (I don't know at what temperature 872066 is triggered, but I'm guessing around 200 F). I ordered and installed a new 872066 and the alarm still sounds. I also used a new IR temperature gauge and couldn't find any areas near the thermostat housing (where the sensors are located) that read above 160F. I removed both the "Sensor, coolant temp. 3852029" and 872066 and tested them with a multimeter to measure the resistance in boiling water and a cup of water with ice. The 3852029 seemed to react appropriately (~1700 ohms in cold water, ~100 ohms in hot water), as did the 872066 (0 ohms in boiling water, no reading at room temp or in cold water). I'm currently entertaining the following possible explanations:
1. The cooling water temperature is too high, causing the 872066 to alarm as designed. If this were the case, I don't understand why the temperature gauge is reading within a normal range and the IR gun doesn't show high temperatures, considering 3852029 and 872066 are right next to each other on the thermostat. Assuming this is the problem, I plan to install a new 3852029 (in case my sensor is not calibrated correctly or something) and switch out the impeller (which I am going to do this week regardless, even though I replaced the entire raw water pump and impeller last year due to water leaks). I suppose the temperature gauge may also be defective or the wiring between the sensor and the gauge? The other idea I have here is to purchase a kit of resistors and build a calibration curve for the gauge (gauge reading per resistance), then cross check this with actual readings in water of various temperatures on a stove to confirm 3852029 is working correctly.
2. The water temperature is not too hot, which means the 872066 is alarming incorrectly. I'm not sure how this could be the case. Perhaps bad wiring from the sensor to the horn? I already replaced 872066, so this seems unlikely.
By the way, this document (https://drive.google.com/file/d/1GNuoMSrUoAwxEKCwM-bq3aMBYuZN79AN/view) has a great engine cooling diagram on page 138 that I figured may be helpful.
I'd appreciate any thoughts or ideas as I am pretty much stumped.
I'm new to the forum and somewhat of a new boat owner (3rd year), so I apologize in advance if this post doesn't follow the rules or my logic is flawed.
I own a 2002 190 Wellcraft Excalibur Sport Platinum with a Volvo Penta 3.0GSP-C engine. After running for 5 minutes @ ~1,500-2000 rpm (or higher) a repeating alarm sound occurs. When I disconnect the wire attached to "Thermo monitor, coolant temp. 872066" (https://www.marinepartseurope.com/e...ts.aspx?Catalog=7744380&Category=30&View=9453), the alarm stops. The temperature on the temperature gauge reads ~175F, which seems to be within the normal operating range (I don't know at what temperature 872066 is triggered, but I'm guessing around 200 F). I ordered and installed a new 872066 and the alarm still sounds. I also used a new IR temperature gauge and couldn't find any areas near the thermostat housing (where the sensors are located) that read above 160F. I removed both the "Sensor, coolant temp. 3852029" and 872066 and tested them with a multimeter to measure the resistance in boiling water and a cup of water with ice. The 3852029 seemed to react appropriately (~1700 ohms in cold water, ~100 ohms in hot water), as did the 872066 (0 ohms in boiling water, no reading at room temp or in cold water). I'm currently entertaining the following possible explanations:
1. The cooling water temperature is too high, causing the 872066 to alarm as designed. If this were the case, I don't understand why the temperature gauge is reading within a normal range and the IR gun doesn't show high temperatures, considering 3852029 and 872066 are right next to each other on the thermostat. Assuming this is the problem, I plan to install a new 3852029 (in case my sensor is not calibrated correctly or something) and switch out the impeller (which I am going to do this week regardless, even though I replaced the entire raw water pump and impeller last year due to water leaks). I suppose the temperature gauge may also be defective or the wiring between the sensor and the gauge? The other idea I have here is to purchase a kit of resistors and build a calibration curve for the gauge (gauge reading per resistance), then cross check this with actual readings in water of various temperatures on a stove to confirm 3852029 is working correctly.
2. The water temperature is not too hot, which means the 872066 is alarming incorrectly. I'm not sure how this could be the case. Perhaps bad wiring from the sensor to the horn? I already replaced 872066, so this seems unlikely.
By the way, this document (https://drive.google.com/file/d/1GNuoMSrUoAwxEKCwM-bq3aMBYuZN79AN/view) has a great engine cooling diagram on page 138 that I figured may be helpful.
I'd appreciate any thoughts or ideas as I am pretty much stumped.
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