Mercruiser 350 MPI Water Pressure Sensor Removal and Installation
HTML-код
- Опубликовано: 3 дек 2024
- In this episode, I remove and clean the Water Pressure Sensor in our Mercruiser 350 MPI. It was full of salt and sand and was giving a low reading on the Garmin causing the engine to go into "Guardian Mode".
When you suck up a good amount of sand and shells through the water pickup on the drive you really need to do the following:
1. open up all the blue drain plugs to let out as much solid debris as possible.
2. open up the raw water pump to see if the impeller got trashed. Might as well replace since you've already got it open.
3. backwash the raw water hose to clean out the drive plumbing
4. backwash the all the hoses and heat exchangers around the back of the engine (where the pressure sensor sits). You can clearly see that all kinds of debris is in there.
5. the acid solution will dissolve shells but it won't have any effect on sand. Refer to #4 above.
6. depending how bad/how much sand got sucked in you may have to open up the thermostat to check and clean. Sand can prevent it from closing fully so the engine will always run too cold.
If you don't get the sand out you'll continue to have low water pressure alarms and guardian mode.
Don't try to do this with the boat in the water. Water will rush in as soon as you disconnect the raw water hose from the drive. Some people pinch the hose w/pliers but I don't think that's a good idea for hose longevity.
Thank you for the great advice! We were also dealing with a Bravo-itis issue which has been fixed with an aftermarket stainless steel part. Everything got flushed out when that was done and sure enough, there was a small beach in there!
This is FN great! I am having the alarm go off at the initial start-up. That is the only time it happens. And yes, like you it has gone into guardian mode a few times but then stops. Only happens at start up. Excited to try this out before I buy a new sensor. THANK YOU for showing me where it is at.
Glad I could help! Frustrated me as well…
I always wondered where that sensor was. No mention of it in the manuals.
It’s a tiny part that can leave you stranded, that’s for sure.
I enjoyed your live lottery drawing! I was hoping for a consolation prize like a toaster or 9” black and white TV…
Merci beaucoup ❤❤❤❤❤
You are very welcome!
Great help 👍
Glad it helped!
Thanks for sharing this video. I do not have 350 but 502s that do not have a water pressure sensor. However, since I have gauges on my Garmin chartplotter I am looking to add these pressures sensor to get a water pressure reading. How much water pressure do you typically get so that I can use this as a reference point. Thx
Buddy, I hate to reach out with an off the wall question, but you seem to know your stuff and to respond to comments.
When you're reaching for the sensor in this video, there is a large purple and black connector just to the left of it. You actually touch it with the back of your hand at exactly the 2:10 mark in the video. Man, if you know and feel charitable, please tell me what that connector is and what the starboard side of the connections run to. My boat only has port side sitting on top of the engine, connected to nothing, and I've got all sorts of non responsive gauges right now.
Thanks either way.
Hey! Thanks for reaching out...That purple plug is to connect the Mercury Vessel View Mobile sensor. That allows you to connect via Bluetooth to monitor engine performance, hours, RPM's, etc. I have the module tucked behind the starboard gunwale where that little recess is to hold the fenders. All of my wiring is back there. It also creates a WiFi network for your boat so you can impress your friends when it shows up on their iPhones out on the water! That's how you perform software updates if you need to.
I also have a NMEA 2000 network set up to interconnect my Garmin MFD (1243 xsv), Radar, Sonar, Fuel flow monitor and stuff like that. It's a really neat way to monitor just about anything on the boat and engine. Of course, you have to buy the module and you have to buy the wiring harness, but if you get stuck, call Mercury tech support and tell them if you are having an issue hooking it up, and they will walk you through everything; at least that was my experience. I don't recall exactly what the wiring issue was, but I ended up NOT connecting something that I thought should be connected and it fixed the problem of not having connectivity.
I have learned a bunch working on the boat because I can't afford a marine mechanic (unless I'm really stuck) or heaven forbid, taking it to a marina where it will sit for weeks and then they charge $200 an hour, at least here in SW Florida.
I remember that there was a purple "Dummy" termination plug that I unplugged and then connected the new harness to. I bought everything on Amazon... Your MFD won't recognize anything unless you have that VesselView Mobile unit installed. Once connected, all sorts of interesting info self-populates onto your dash. I get water temp, fuel pressure, engine hours, anywhere there is a sensor connected to that engine, you get the data.
Feel free to reach out with any other questions. If I can't answer them, I will point you in the right direction.
Hope this helps! Happy Boating!
Hey brother love your videos , and thanks for the knowledge.
I have a question about the vessel view system . I got twin optimax 200 on my center console and came with 2 simrads go9 screens that are not connected to anything on the boat. What would be my process for hooking up my engines data to show in the simrads ?
I’ve been trying to figure this out for a while now but couldn’t figure it out exactly how to get it done between the vessel view , smartcraf gateway , vessel view connect / mobile , NMEA 2000 , Ethernet , can , bus and so on .
Just thought about trying
Them one by one till I got it right but lord all mighty these babies cost an arm and a leg ! 😢
Really appreciate all the help .
Can the sensor be changed with the boat in the water
Yes, the process takes just a few seconds and the hole where water flows through is small.
Hi I had my water pressure sensor replaced on my 350 Horizon because my smart gauges were alarming every 2 minutes saying "water pressure sensor faulty". But I could still drive the boat normally.
Now that is replaced, I can't rev the boat above 1200rpm. It still starts and idles fine. Is this guardian mode?
Hi Tony...I don't know if you are in salt water or fresh, but down here in SW Florida, the water is very salty and the sand is powdery so it can get stuck in that sensor.
Actually, after I made this video, I had the engine go into Guardian mode while cruising along at about 30 MPH. As soon as I put it back into neutral it reset and I was able to accelerate again, only to have the same thing happen. I removed the water pressure sensor out on the water and there was a chunk of debris lodged against the sensor! That didn't take long... I bought a new spare to keep on board in case it happens again.
Guardian mode returns the engine to idle, which should be about 600 RPM, not 1200. I wonder if you have an obstruction in the fuel line? I would check your fuel filters and fuel/water separator because the increased vacuum on the obstructed fuel line can cause it to collapse on itself and restrict the fuel flow. Also, there is a neutral safety switch that can get out of whack but that usually occurs at a higher RPM. Make sure you have good water flow through the engine and outdrive. Also, check to make sure you don't have anything wrapped around your prop shaft like fishing line or rope. A loose plug wire can be another culprit. I just bought a set of service manuals for my 350MPI for just this reason...$108.00 for a set of 4 vs. $200 an hour at the dealership, not to even mention a tow possibly!
Let me know if you have any findings and I will keep researching this for you.
Thank you for your video, very informative, I’m using the same product to clean the barnacles very good and cheaper.