High Water Pressure on gauge

[Wheelman]

NPHE wrote: Update. After raising my engine 1/4 inch and running it there gauge showed same thing. Raised it two more times until I got a high temp alarm. Showed 30 lbs plus when alarm sounded. Lowered to original height it was when I purchased it and said I give up and think I just have to live with it. I am not happy about that but am not sure what else to do. I’m wondering now if it is just a characteristic of a Sabre hull.

I have the exact same year model boat and motor, you can see clearly below that it’s not a characteristic to run that high of water psi all the time in the video. Curious how high your rooster tail is at WOT?

https://youtu.be/lEIqlRR9cqI

[JEH in La]

Definitely not a Sabre Hull problem. If anything at all, the only common link here is the 150 4 Stroke Mercury. Cajunhunter 67 has a good idea to post on BBC 4 Stroke Forum. There are some experienced Mercury Techs. on the forum and they will have some insight I would think. European Marine should know if this is a common problem or at least tell you what to check for.

[JEH in La]

Wheelman wrote:

NPHE wrote: Update. After raising my engine 1/4 inch and running it there gauge showed same thing. Raised it two more times until I got a high temp alarm. Showed 30 lbs plus when alarm sounded. Lowered to original height it was when I purchased it and said I give up and think I just have to live with it. I am not happy about that but am not sure what else to do. I’m wondering now if it is just a characteristic of a Sabre hull.

I have the exact same year model boat and motor, you can see clearly below that it’s not a characteristic to run that high of water psi all the time in the video. Curious how high your rooster tail is at WOT?

Thanks for posting Wheelman. His jackplate is set “even” between the inner to outer plates. I don’t think he is trimming too much. I drove his boat ran 63 MPH at that jackplate setting. I have never seen a water pressure gauge act this way.

[Wheelman]

JEH in La wrote:

Wheelman wrote:

NPHE wrote: Update. After raising my engine 1/4 inch and running it there gauge showed same thing. Raised it two more times until I got a high temp alarm. Showed 30 lbs plus when alarm sounded. Lowered to original height it was when I purchased it and said I give up and think I just have to live with it. I am not happy about that but am not sure what else to do. I’m wondering now if it is just a characteristic of a Sabre hull.

I have the exact same year model boat and motor, you can see clearly below that it’s not a characteristic to run that high of water psi all the time in the video. Curious how high your rooster tail is at WOT?

Thanks for posting Wheelman. His jackplate is set “even” between the inner to outer plates. I don’t think he is trimming too much. I drove his boat ran 63 MPH at that jackplate setting. I have never seen a water pressure gauge act this way.

I was actually wondering if he wasn’t trimming enough, is it pegged like in this video? This was running the Tempest prop and jackplate flush (the way it came from the factory), wasn’t trimmed up as high and out to 15psi because water wasn’t as smooth. There’s an electronic trim limiter on the 150 4-stroke and I’m wondering if his is possibly programmed too low.

[JEH in La]

Wheelman I was looking at your water pressure gauge and it is not steady like I have always seen with the Optimax and ProXS. Yours pegs out too so maybe that is a characteristic of the Merc. 4 Stroke. NPHE has owned Yamaha and Mercury ProXS and has never seen the water pressure gauge act this way.
I do know that he can throw a good rooster tail if he trims up too much so I don’t think there is an issue of a trim limiter with his motor.
We just don’t understand why the water pressure is not a steady reading because we have never encountered this with boat ownership going back many years. That’s why he and I think that this should not be normal and would like to solve it if possible.

[Wheelman]

JEH in La wrote: Wheelman I was looking at your water pressure gauge and it is not steady like I have always seen with the Optimax and ProXS. Yours pegs out too so maybe that is a characteristic of the Merc. 4 Stroke. NPHE has owned Yamaha and Mercury ProXS and has never seen the water pressure gauge act this way.
I do know that he can throw a good rooster tail if he trims up too much so I don’t think there is an issue of a trim limiter with his motor.
We just don’t understand why the water pressure is not a steady reading because we have never encountered this with boat ownership going back many years. That’s why he and I think that this should not be normal and would like to solve it if possible.

In the first video it doesn’t do that though, I showed the 2nd video where it was pegged and if you notice the trim is lower than in the first video as the angle of the lower unit affects the amount of water psi. The outboard doesn’t come standard with a water psi sensor, so maybe there’s an issue with the way it’s installed if you can’t get the water psi to drop with excessive trimming even at lower speeds as I don’t think there’s any difference with the design of the lower unit that the non torque master 2-stroke gearcases.

[Cajunhunter67]

I’m not familiar with the 150 FS, but the over temp horn going off with 30 psi showing throws a red flag for me.
It may be nothing more than a gauge issue, but you need to make sure your pressure indication is correct.

[JEH in La]

Wheelman wrote:

JEH in La wrote: Wheelman I was looking at your water pressure gauge and it is not steady like I have always seen with the Optimax and ProXS. Yours pegs out too so maybe that is a characteristic of the Merc. 4 Stroke. NPHE has owned Yamaha and Mercury ProXS and has never seen the water pressure gauge act this way.
I do know that he can throw a good rooster tail if he trims up too much so I don’t think there is an issue of a trim limiter with his motor.
We just don’t understand why the water pressure is not a steady reading because we have never encountered this with boat ownership going back many years. That’s why he and I think that this should not be normal and would like to solve it if possible.

In the first video it doesn’t do that though, I showed the 2nd video where it was pegged and if you notice the trim is lower than in the first video as the angle of the lower unit affects the amount of water psi. The outboard doesn’t come standard with a water psi sensor, so maybe there’s an issue with the way it’s installed if you can’t get the water psi to drop with excessive trimming even at lower speeds as I don’t think there’s any difference with the design of the lower unit that the non torque master 2-stroke gearcases.

NPHE is second owner so we’re not sure that the water psi sensor is installed correctly or not. He did not get a manual for his motor either so we just aren’t sure about the 4 Stroke details.
Wheelman do you think the water pressure is actually over 30 psi?
The water psi sensor simply looks like a 1/8″ pipe connection that transitions to the plastic tubing that leads to the gauge. Why is it called a “Sensor”?
The only thing I would do at this point is take it off and see if it’s not partially plugged or something.
Would you please take a picture of your sensor so we can compare it to the one he has?  Thanks in advance.

[Wheelman]

JEH in La wrote:

Wheelman wrote:

JEH in La wrote: Wheelman I was looking at your water pressure gauge and it is not steady like I have always seen with the Optimax and ProXS. Yours pegs out too so maybe that is a characteristic of the Merc. 4 Stroke. NPHE has owned Yamaha and Mercury ProXS and has never seen the water pressure gauge act this way.
I do know that he can throw a good rooster tail if he trims up too much so I don’t think there is an issue of a trim limiter with his motor.
We just don’t understand why the water pressure is not a steady reading because we have never encountered this with boat ownership going back many years. That’s why he and I think that this should not be normal and would like to solve it if possible.

In the first video it doesn’t do that though, I showed the 2nd video where it was pegged and if you notice the trim is lower than in the first video as the angle of the lower unit affects the amount of water psi. The outboard doesn’t come standard with a water psi sensor, so maybe there’s an issue with the way it’s installed if you can’t get the water psi to drop with excessive trimming even at lower speeds as I don’t think there’s any difference with the design of the lower unit that the non torque master 2-stroke gearcases.

NPHE is second owner so we’re not sure that the water psi sensor is installed correctly or not. He did not get a manual for his motor either so we just aren’t sure about the 4 Stroke details.
Wheelman do you think the water pressure is actually over 30 psi?
The water psi sensor simply looks like a 1/8″ pipe connection that transitions to the plastic tubing that leads to the gauge. Why is it called a “Sensor”?
The only thing I would do at this point is take it off and see if it’s not partially plugged or something.
Would you please take a picture of your sensor so we can compare it to the one he has?  Thanks in advance.

Does your water psi change readings at all depending on speed and trim or is it just pegged at wot? Thread below states 12-43.5psi at wot is normal, hope that helps.
http://www.bbcboards.net/showthread.php?t=575295

[JEH in La]

Wheelman wrote:

JEH in La wrote:

Wheelman wrote:
In the first video it doesn’t do that though, I showed the 2nd video where it was pegged and if you notice the trim is lower than in the first video as the angle of the lower unit affects the amount of water psi. The outboard doesn’t come standard with a water psi sensor, so maybe there’s an issue with the way it’s installed if you can’t get the water psi to drop with excessive trimming even at lower speeds as I don’t think there’s any difference with the design of the lower unit that the non torque master 2-stroke gearcases.

NPHE is second owner so we’re not sure that the water psi sensor is installed correctly or not. He did not get a manual for his motor either so we just aren’t sure about the 4 Stroke details.
Wheelman do you think the water pressure is actually over 30 psi?
The water psi sensor simply looks like a 1/8″ pipe connection that transitions to the plastic tubing that leads to the gauge. Why is it called a “Sensor”?
The only thing I would do at this point is take it off and see if it’s not partially plugged or something.
Would you please take a picture of your sensor so we can compare it to the one he has?  Thanks in advance.

Does your water psi change readings at all depending on speed and trim or is it just pegged at wot? Thread below states 12-43.5psi at wot is normal, hope that helps.
http://www.bbcboards.net/showthread.php?t=575295

Thanks for the help Wheelman. I’m going to get NPHE on here to answer your question with more information than I can give. I’m pretty sure his gauge only goes to 30 psi., so wow, 43 psi is normal?  No wonder it’s pegged out.
This is great information that we didn’t know at this point. All of our experience is Yamaha and ProXS and both of these have much lower pressure.

[NPHE]

The gauge actually fluctuates from high to low and back to high while running and experimenting with trim. It does not stay pegged out and changes in pressure are sometimes sudden like it loses pressure. This is what bothers me, it just doesn’t seem right. I replaced the BassCat gauge with a new one and both gauges showed the same thing. The mechanic at Cabella’s tried another gauge and it read the same. So I don’t think it’s a gauge problem. I just don’t know if and when my pressure actually does go down that I can trust these readings. Why wouldn’t BassCat install a gauge with a larger reading if 43.5 is correct for this engine pressure?

[Wheelman]

NPHE wrote: The gauge actually fluctuates from high to low and back to high while running and experimenting with trim. It does not stay pegged out and changes in pressure are sometimes sudden like it loses pressure. This is what bothers me, it just doesn’t seem right. I replaced the BassCat gauge with a new one and both gauges showed the same thing. The mechanic at Cabella’s tried another gauge and it read the same. So I don’t think it’s a gauge problem. I just don’t know if and when my pressure actually does go down that I can trust these readings. Why wouldn’t BassCat install a gauge with a larger reading if 43.5 is correct for this engine pressure?

Sounds like you may have debris causing intermittent readings would be my guess unless you’re running really rough water and surfacing the lower unit. What I find strange is the outboard doesn’t come standard with water psi capability though it’s on more non performance applications that don’t run jackplates than performance bass boats and honestly feel it was designed more for pontoon boats based on the super soft rubber mounts like Evinrude specifically uses below. I upgraded mine to the new Pro XS version which came from the Sea Pro model as I had bolts/nuts loosening up that I’ve never had to check on an outboard before as well as excessive wear on the bracket and troubles controlling chinewalk. Since you bought the boat used and not sure how hard the previous owner ran it you might go over it, you can search my other threads for details if interested.

[Midnight Rider]

The high temperature sensor has nothing to do with the water pressure gauge. The temperature sensor is an on/off switch that sets off the horn/beeper when the temp reaches whatever the sensor is supposed to be set to…generally, that is around 180 degrees (at least it is on a Yamaha SHO). If you have standard Mercury gauges (comes on the Sabre), it’s simply a fitting on the engine that is installed after removing a bolt that is on the water jacket. If you remove the cowling, you should be able to spot it easily, as it is nothing more than a brass nipple with tubing attached. The gauge is a simple mechanical analog gauge. It sounds like a poppet valve is stuck, but I’m not sure your engine even has a poppet. It does have a thermostat, which could be suspect.

It sounds like you might have blockage in the water passages somewhere. It doesn’t take much, BELIEVE ME. Upper maximum pressure on my SHO and my Sabre FTD is 25 psi, and will drop to as low as 11 psi when trimmed up all the way. I’ve not personally heard of an outboard that puts out 43 psi at any time.

[Wheelman]

Midnight Rider wrote: The high temperature sensor has nothing to do with the water pressure gauge.  The temperature sensor is an on/off switch that sets off the horn/beeper when the temp reaches whatever the sensor is supposed to be set to…generally, that is around 180 degrees (at least it is on a Yamaha SHO).  If you have standard Mercury gauges (comes on the Sabre), it’s simply a fitting on the engine that is installed after removing a bolt that is on the water jacket. If you remove the cowling, you should be able to spot it easily, as it is nothing more than a brass nipple with tubing attached. The gauge is a simple mechanical analog gauge.  It sounds like a poppet valve is stuck, but I’m not sure your engine even has a poppet.  It does have a thermostat, which could be suspect.

It sounds like you might have blockage in the water passages somewhere.  It doesn’t take much, BELIEVE ME.  Upper maximum pressure on my SHO and my Sabre FTD is 25 psi, and will drop to as low as 11 psi when trimmed up all the way. I’ve not personally heard of an outboard that puts out 43 psi at any time.

My understanding is he got the high temp alarm from raising the motor and his pressure gauge apparently isn’t working properly as it got hot from lack of water. I would think an obstruction would cause it read low, regardless you can see in one of the videos I posted where the 30psi gauge is pegged while running WOT. I’ll admit it freaked me out the first time that happened as I thought I had lost all water psi then when I slowed down I realized it dropped from 30psi. The faster you go the more you cram water into the intakes and cause an increase in pressure, the closer the lower unit is to being parallel to the water’s surface the higher the psi reading will be.

[Midnight Rider]

Wheelman wrote:

Midnight Rider wrote: The high temperature sensor has nothing to do with the water pressure gauge.  The temperature sensor is an on/off switch that sets off the horn/beeper when the temp reaches whatever the sensor is supposed to be set to…generally, that is around 180 degrees (at least it is on a Yamaha SHO).  If you have standard Mercury gauges (comes on the Sabre), it’s simply a fitting on the engine that is installed after removing a bolt that is on the water jacket. If you remove the cowling, you should be able to spot it easily, as it is nothing more than a brass nipple with tubing attached. The gauge is a simple mechanical analog gauge.  It sounds like a poppet valve is stuck, but I’m not sure your engine even has a poppet.  It does have a thermostat, which could be suspect.

It sounds like you might have blockage in the water passages somewhere.  It doesn’t take much, BELIEVE ME.  Upper maximum pressure on my SHO and my Sabre FTD is 25 psi, and will drop to as low as 11 psi when trimmed up all the way. I’ve not personally heard of an outboard that puts out 43 psi at any time.

My understanding is he got the high temp alarm from raising the motor and his pressure gauge apparently isn’t working properly as it got hot from lack of water. I would think an obstruction would cause it read low, regardless you can see in one of the videos I posted where the 30psi gauge is pegged while running WOT. I’ll admit it freaked me out the first time that happened as I thought I had lost all water psi then when I slowed down I realized it dropped from 30psi. The faster you go the more you cram water into the intakes and cause an increase in pressure, the closer the lower unit is to being parallel to the water’s surface the higher the psi reading will be.

Agreed….first hand experience: if the water pressure is low, it is generally either the water pump, or a blockage somewhere in the cooling passages. There are some small passages in the cooling system that can get clogged with small amounts of sand/debris. A poppet valve decreases pressure as flow/pressure increase, but it would have to be stuck closed and as I mentioned, I’m uncertain whether his engine even has one. Yes, the pressure is totally dependent on where the foot of the motor is relative to the “wave” created behind the boat’s hull.

Also, mine, which had a partial blockage in the cooling jackets would ONLY run hot after idling for 15-20 minutes due to lack of flow.  What is the pressure on this motor when idling? Normally, it barely even moves the needle off of zero at 6-900 rpm

[Author]

Posts