Good morning.
I recently purchased a 2005 Mercury 150 Saltwater motor. I did a compression check and it ran great in a tub.
The motor looks like it's a year old, not 12 years old.
I took it to the river and made it a hundred yards and the overheat alarm sounded, but no reaction from the rev limiter.
I have replaced the popet valve, thermostats, impeller, and what I thought to be the overheat alarm sensor on the port side head.
I also found the purple wire cut at the module, hence no reduction in rpms.
I then put it under load (it runs fine in the driveway) by running it on the trailer at 2000 rpms for 10 minutes, no alarm, great.
Back to the river with friends, boat running great, 100 yards alarm again. This time I unplug what I now know
to be the overheat sensor on the starboard head, and no alarm.
Did the test on the sensor and it triggered at about 170 degrees, the book says the sensor triggers at 235 degrees
So I am replacing that today.
I am reading temps on the heads in the 170 or so and have seen a temp of 184 degrees at the highest.
I don't think the motor is overheating, as it doesn't labor even a little on restart.
I figure that replacing the sensor won't cure my problem at the rate this is going, I've been back and forth to the river so many times,
I've lost count. So my questions are, what is an acceptable operating temp at the heads for this motor, and can I remove the heads
without replacing the rubber seals if they are in good condition.
The motor is on a 1996 Trophy 1802, replacing the Force 120 that blew up.
The extra power is awesome for the 15 seconds I was able to jump on it, and the anticipation of running this boat is taking its toll on me!
I recently purchased a 2005 Mercury 150 Saltwater motor. I did a compression check and it ran great in a tub.
The motor looks like it's a year old, not 12 years old.
I took it to the river and made it a hundred yards and the overheat alarm sounded, but no reaction from the rev limiter.
I have replaced the popet valve, thermostats, impeller, and what I thought to be the overheat alarm sensor on the port side head.
I also found the purple wire cut at the module, hence no reduction in rpms.
I then put it under load (it runs fine in the driveway) by running it on the trailer at 2000 rpms for 10 minutes, no alarm, great.
Back to the river with friends, boat running great, 100 yards alarm again. This time I unplug what I now know
to be the overheat sensor on the starboard head, and no alarm.
Did the test on the sensor and it triggered at about 170 degrees, the book says the sensor triggers at 235 degrees
So I am replacing that today.
I am reading temps on the heads in the 170 or so and have seen a temp of 184 degrees at the highest.
I don't think the motor is overheating, as it doesn't labor even a little on restart.
I figure that replacing the sensor won't cure my problem at the rate this is going, I've been back and forth to the river so many times,
I've lost count. So my questions are, what is an acceptable operating temp at the heads for this motor, and can I remove the heads
without replacing the rubber seals if they are in good condition.
The motor is on a 1996 Trophy 1802, replacing the Force 120 that blew up.
The extra power is awesome for the 15 seconds I was able to jump on it, and the anticipation of running this boat is taking its toll on me!
