Low water pressure alarm

M

Matt N

New Member
Oct 11, 2021
23
Boat Info
2016 Sundancer 350
Engines
Twin 350 Mercuiser Bravo III Drives
Going into guardian mode at around 3K rpm with alarm msg "Port Engine. Engine Power Limited". I had a tech scan the codes and it's apparently a low water pressure fault.

A little more back story... This started happening after a recent haul out. Just got the bottom painted, anodes changed and engines flushed, no mechanical work done. As soon as I tried to get on plane, the alarm started going off. It took me about 2 hours to get back to slip going 10mph. Before the codes were scanned, I wasn't super concerned b/c both engines were running at about 155 degrees the entire trip back, so it at least wasn't an overheating issue. Figured a bad sensor was throwing into guardian mode.

This is the strange part. When the tech looked into the alarm history, it showed the water pressure was only at 2.67psi when the alarm went off. However, back at the slip it shows 10psi when revved to 3K rpm in neutral.

The tech believes there is a blockage in the outdrive or in the transom assembly and the boat needs to be hauled out again to take off the drive and inspect.

Another note, when the boat was out of water I flushed the engines with muffs. I noticed the engine temps creep up to 175 when they never go above 160 in the water, so I didn't run them for too long. Maybe this could've messed something up or damaged the impeller, but then why would the water pressure be back up at the slip?

Is there anything I can check before having to haul out again? I'm going to be replacing risers and manifolds next year, but I got them inspected a year ago and tech said they look great and engines never go over 160 in water, so don't think that's the issue. Could it be the impeller even though pressure is ok at slip?
 
Maybe picked up a plastic bag while cruising?
 
That's possible, I'm just trying to figure out if there's anything else I can troubleshoot before having to get boat hauled out...
 
Espos4 said:
Swap the pressure sensors between motors and go for a ride.
Click to expand...

Might be a dumb question, but if I remove the pressure sensor with the boat in the water, will water spew out?
 
Matt Norton said:
Might be a dumb question, but if I remove the pressure sensor with the boat in the water, will water spew out?
Click to expand...
Pressure sensor is likely near the top of the engine, on the back side. It’s a small fitting, only like 1/4 or 5/16 hole. If the engine is off water is not going to shoot out. Should be an easy swap.
 
Matt Norton said:
Going into guardian mode at around 3K rpm with alarm msg "Port Engine. Engine Power Limited". I had a tech scan the codes and it's apparently a low water pressure fault.

A little more back story... This started happening after a recent haul out. Just got the bottom painted, anodes changed and engines flushed, no mechanical work done. As soon as I tried to get on plane, the alarm started going off. It took me about 2 hours to get back to slip going 10mph. Before the codes were scanned, I wasn't super concerned b/c both engines were running at about 155 degrees the entire trip back, so it at least wasn't an overheating issue. Figured a bad sensor was throwing into guardian mode.

This is the strange part. When the tech looked into the alarm history, it showed the water pressure was only at 2.67psi when the alarm went off. However, back at the slip it shows 10psi when revved to 3K rpm in neutral.

The tech believes there is a blockage in the outdrive or in the transom assembly and the boat needs to be hauled out again to take off the drive and inspect.

Another note, when the boat was out of water I flushed the engines with muffs. I noticed the engine temps creep up to 175 when they never go above 160 in the water, so I didn't run them for too long. Maybe this could've messed something up or damaged the impeller, but then why would the water pressure be back up at the slip?

Is there anything I can check before having to haul out again? I'm going to be replacing risers and manifolds next year, but I got them inspected a year ago and tech said they look great and engines never go over 160 in water, so don't think that's the issue. Could it be the impeller even though pressure is ok at slip?
Click to expand...
Matt did you find out what is wrong with your engine? I have just experienced the same with my stb engine, after replacing the heat exchangers, transmissions coolers last weekend while taking a ride up the river my stb engine water pressure alarm went off. I limped back to the dock, and replaced the water sensors on both engines, 8.1s $178 a piece, test ride today while at the dock water temp fine 165, but once out on the water at about 1400rpm, the alarm sounded and the water pressure showed .7 but the engines were still 165, and water was pumping strong. Having a friend come over tomorrow and help with a computer. The alarm still sounds every 2 minutes with two beeps. don't want to switch the sensors as the port one is a real pain to get to. easier to get to the stb one.
 
Setimos said:
Matt did you find out what is wrong with your engine? I have just experienced the same with my stb engine, after replacing the heat exchangers, transmissions coolers last weekend while taking a ride up the river my stb engine water pressure alarm went off. I limped back to the dock, and replaced the water sensors on both engines, 8.1s $178 a piece, test ride today while at the dock water temp fine 165, but once out on the water at about 1400rpm, the alarm sounded and the water pressure showed .7 but the engines were still 165, and water was pumping strong. Having a friend come over tomorrow and help with a computer. The alarm still sounds every 2 minutes with two beeps. don't want to switch the sensors as the port one is a real pain to get to. easier to get to the stb one.
Click to expand...

Unfortunately not yet. I took it in for service and of course it worked fine on the way there. My trim senders haven't been working for a while and the tech thinks it's causing other sensors to go haywire b/c it's on a reference line. I do sometimes get random alarms when there doesn't appear to be anything wrong. However, the trim senders haven't worked for quite a while and never got a low water pressure alarm before. Since the alarm didn't throw on the way there, I was hoping it was a one time thing. But when I left, it happened again as soon as increased rpms...

I'm due for transom assembly service which replaces the senders, so probably going to try that next. Although I'm not extremely confident it's actually related, since I never had this problem before while the senders didn't work. Since it's getting hauled out and drive removed anyway, I'll probably have them try to inspect the intake hoses to see if anything is actually jammed in there restricting the water pressure under load.

I'm not really sure what else to try at this point. I'll post here if any updates, please let me know what you end up finding as well.
 
You must log in or register to reply here.

Forum statistics

Threads
113,115
Messages
1,426,324
Members
61,027
Latest member
NeilS
Back
Top