Bravo 1 water pressure issues

[alldodge]

My part number is 47-8M0104229.

Your good, that is the latest part number for the impeller

Directly above the distribution housing a hose goes into a Tee. Take the hoses off it and see if the ones going to the risers have a smaller diameter hole

 

[skyman2112]

have you tried replacing the water pressure sensor?

working on a resistor package for that pesky sensor,

did you ever get a resistor package for this pesky water sensor? Does the voltage increase or decrease as the water pressure rises? I'm still having problems at idle when the engine warms up, just not quite enough pressure to always keep the alarm off
. Even though I replaced everything you can think of ,even had the lower unit off for some unrelated work and didn't see any problems in the hoses.Tons of water flow, never runs hot. 3rd water pressure sensor. new poppet valve spring, new pump housing, new impeller.

 

[skyman2112]

have you tried replacing the water pressure sensor?

working on a resistor package for that pesky sensor,

did you figure out a way to put resistors on this pesky sensory I still have to rev the engine every time i start it to keep the idle pressure readings up. How about a voltage divider in the 5v supply line Reduce it to 4.5 volts so its reads a higher psi..

 

[skyman2112]

Your good, that is the latest part number for the impeller

Directly above the distribution housing a hose goes into a Tee. Take the hoses off it and see if the ones going to the risers have a smaller diameter hole

hi again still struggling with my low pressure alarm. I see a Tee just above the pump output line that goes to the exhaust riser. Its a small diamter hose not sure what i should look for? Heres a video of my scan tool readings done with the boat in the water, not on shore. Then a video of the water flow through the intake hose with a hose connected inside.

 

[Bt Doctur]

Bravoitis occurs at the transom housing side primarily and rarely at the gimbal side. This is an extreme case
click to enlarge

 

[alldodge]

Is flyer2112 and skyman2112 the same person?

Listening to the motor starting and it taking some cranking to get it going, can you check some voltages. Check water pressure sensor and it should be 5V on Gray wire. Measure it from block ground and also from the Black/Pink on the same sensor to see if there is any difference

 

[skyman2112]

Bravoitis occurs at the transom housing side primarily and rarely at the gimbal side. This is an extreme case
click to enlarge

yeah thats the most common reply i hear of. Did you see my water flow video? Does it seem restricted to you?
I was just gonna reduce the input voltage to the water pressure sensor by using a voltage divider. You wouldnt happen to know the values of resistors i could use for that would you? I think im shooting for around 4.2 - 4.3 volts. Let me know, thanks

 

[skyman2112]

Is flyer2112 and skyman2112 the same person?

Listening to the motor starting and it taking some cranking to get it going, can you check some voltages. Check water pressure sensor and it should be 5V on Gray wire. Measure it from block ground and also from the Black/Pink on the same sensor to see if there is any difference

yes its both my profiles, i couldnt log in 1 day. The motor has a 5psi oil pressure switch i was told to delay starting. Its always started this way since new. I will check those voltages. It has a 3 wire sensor so its no longer grounded to the case of the cooler as in the 2 wire sensors.

 

[jbcurt00]

yes its both my profiles, i couldnt log in 1 day.

We can merge the 2 profiles into 1.

Which user name would you prefer?

@scott.cooper
@colonel_sanders

 

[skyman2112]

We can merge the 2 profiles into 1.

Which user name would you prefer?

@scott.cooper
@colonel_sanders

ill keep skyman2112. Did you see my water flow video? Does it look sufficient?

 

[alldodge]

I don't see an issue with the water flow, but where just looking at a garden hose. If your not in salt water I also don't think bravoits would be an issue

I also posted the wrong cooling system for your motor, the previous was non-cat motor. This is the cat motor and look at item 20 the Tee. Parts list show it as Green (item 20) and if this is the wrong size it will allow to much water to bypass

https://www.mercruiserparts.com/bam/subassembly/31794/15323/210

 

[skyman2112]

that makes sense, this is the first year of the catalyst motors. Would be easy to use the wrong T on the assembly line. Would explain everything especially why i dont have a problem untill the thermostat opens and decreases backpressure. Ill check for the correct part number

 

[skyman2112]

Well dangit it has the green T installed. Maybe its just a design flaw that allows a little to much water to the exhaust since its the first year catalyst motor. Look how many places the water splits off to the exhaust its no wonder it has any back pressure at all. Where could i add a restriction to increase back pressure without limiting water flow to the exhaust too much

 

[alldodge]

Be good if @muc would give an opinion, but my next stop would be to contact Merc tech support

If an additional restriction is used, it would be unsure about what would happen with the sensors

 

[skyman2112]

Be good if @muc would give an opinion, but my next stop would be to contact Merc tech support

If an additional restriction is used, it would be unsure about what would happen with the sensors hoses and see what happens.

 

[skyman2112]

It was a restriction that allowed just enough water through to function but made it hard to build pressure at start up.