Aftermarket water pressure sensor

Looks like I have to replace the water pressure sensor on my 5.0 MPI for the second time in two years. This is the sensor on the steering cooler with a Mercury part number of 8m6000623.

From a brief search online it looks like this part is known to fail often. For a $90 - $130 sensor, I would hope to get more than a single season out of it.

I ended up ordering an aftermarket sensor on Amazon for a little over $30 dollars. My thinking is that this sensor may very well have come off the very same assembly line. At best, I'll get the same lifespan out of the sensor and will buy a couple extra to keep on-board. At worst, the aftermarket sensor will be a piece of junk and I'll be out only $30.

Has anybody tried these aftermarket sensors? Anybody out there keep these sensors on hand in case they fail?

I think they are known to fail much faster for those who boat in sandy areas. So not necessarily a bad sensor, just a result of the boating conditions. I never had a problem with either of mine in a twin engine boat and logged hundreds of hours over almost 6 years lake boating, rarely in shallow water, probably never sandy water. I think the increased failure you are seeing might be another result of the higher overall maintenance cost for saltwater boating. On the upside, you get a much better boating experience. As for aftermarket parts, I've never been a fan. Based on my personal experience and observations of the woes of others, they often seem to cause more problems than the money saved is worth. Just my opinion. Considering the minimal space they consume and the frequent failure you are seeing, I would definitely carry spares.

Update: Mercury OEM 8M6000623, SmartCraft SEA PUMP CKT alarm, Engine water pressure pegged or reads zero.

I have just had my fourth senor alarm and associated power limitation in three seasons for water pressure on engines that are clearly working fine. BOTTOM LINE: Tap water pressure sensor to dislodge grit and restore normal operation.

Here's the back story. First, the previous three: The first (SEA PUMP CKT HI), I replaced the sensor ($140!). The next two self cleared. Each was associated with either kicked up sediment in shallows, or visible surface debris. All alarms have occurred either at power down or power up. I have not yet been on plane and had a motor taken away.

On the fourth alarm, we powered down in shallow water in a channel, and on power up, got the alarm and power reduction. (Smart Craft read "OK" above the press gauge, but the gauge read mostly 0.0 with the engine running and with added power). Running up to about 1100 RPM (max without setting off that miserable alarm), every once in a while the gauge would jump up to (a low reading of ) 6 or 7 PSI. I decided to power up when that happened, and noticed at about 2500 RPM, the gauge jumped up to normal pressure, but not before triggering the alarm and power down. SO, the next time I got the 6 or 7 PSI indication, I throttled up quickly and got the normal gauge reading to kick in before triggering the alarm, and we made it home on plane. At power down, the alarm resumed.

Once in port, I had a friend monitor the gauge, and with the engine off and gauge stuck with a positive reading of around 7 PSI, went and banged on the sensor with some vice grips (follow the water line to just past the drive belt, low on 8.1S V drives). The gauge immediately went to the correct 0.0 reading and worked fine after that. SO, if stuff gets caught in there, it looks like you can knock it loose.