WATER PRESSURE Smartcraft reading

[pbuzz3323]

My smartcraft reads .5 and .6 water pressure at idle..Is that low?...That is on the driveway muffs.....2003 searay..5.0 MPI, 260 Hp engine...S/N..0m624941

 

[Bt Doctur]

Re: WATER PRESSURE Smartcraft reading

Never seen a water pressure gauge on a I/O
whats it suppoed to do.It would seem that if the pressure goes up ,you have some kind of restriction.

 

[Silvertip]

Re: WATER PRESSURE Smartcraft reading

What good is measuring water pressure on muffs? You have house water system pressure feeding the engine. Even if the water pump wasn't working the gauge could still show some pressure. It proves nothing. It also matters where you have the water pressure gauge hooked up.

 

[newport dave]

Re: WATER PRESSURE Smartcraft reading

Your a little low, and it may be due to the fact that your on the hose, but in the water at idle the seapump pressure should be between 1 and 2 PSI. I would verify the pressure at higher RPMS, you should have about 10PSI at cruise speed.

 

[Coors]

Re: WATER PRESSURE Smartcraft reading

Yeah, an add-on, I added one.
Pressure above 1500 rpm is about 15.

 

[pbuzz3323]

Re: WATER PRESSURE Smartcraft reading

It came with the boat New from searay..I just discovered what this reading was when I changed the Impeller and Thermostat..When I increased the throttle it went to around .9..Kinda low but thats in the driveway..I will hopefully have higher numbers when its in the water..all hoses were clear but I wasnt able to check from the riser/hose connection and back. Im told that can be an area of restriction alot of times. Aside from that its running perfect now...Is it a a tough job to clean the risers out and replace the gaskets? Looks like only a few bolts and 2-3 gaskets on each side.

 

[45Auto]

Re: WATER PRESSURE Smartcraft reading

My Smartcraft runs just over 3 PSI at idle (muffs or in water) and just over 10 PSI at cruising speed. Never had it above idle on muffs.

Mine's a Bravo 3 with a belt-driven seawater pump, I'm assuming yours is probably an Alpha?

Do you know what it was reading before you changed the impellor?

 

[pbuzz3323]

Re: WATER PRESSURE Smartcraft reading

I have the same one..Bravo 3...Unsure of the reading before changing impeller But never had a problem until last year with impeller going bad...It was never changed until this year. I did the Impeller and t stat

 

[45Auto]

Re: WATER PRESSURE Smartcraft reading

There may be a resistance spec for the pressure transducer in the Merc manual you could check. Is it possible some debris from the old impellor is plugging the port to the transducer? It's the brass transducer mounted on the side of the seawater pump.

You can see that the port has to make a right angle to get to it. Wouldn't be hard for a piece of trash to partially block it.

Does it try to overheat on the muffs? Best bet would probably be try it in the water and keep a VERY close watch on the temp. If it starts getting hot shut it down and plan on more troubleshooting of the cooling system.

Only other thing I can think of to try would be swapping the pressure transducer with another one to check it - possibly yours was damaged during the impellor change.

 

[newport dave]

Re: WATER PRESSURE Smartcraft reading

They moved the sensor from the seawater pump (I think in '02) to the power steering cooler. You will see lower pressures from the sensor mounted on the cooler vs the sensor mounted on the pump.

 

[45Auto]

Re: WATER PRESSURE Smartcraft reading

Didn't know they had moved it. Mine's a 2003 and it's on the pump.

 

[pbuzz3323]

Re: WATER PRESSURE Smartcraft reading

Does it try to overheat on the muffs? Best bet would probably be try it in the water and keep a VERY close watch on the temp. If it starts getting hot shut it down and plan on more troubleshooting of the cooling system.

Its fine on the muffs now..the old impeller came out in 1 whole piece..no broken pieces. I didnt see anything on the seawater pump that I had to unplug..maybe it is on the power steering cooler...If im ok in the water (Temp wise) but the number is still low Is it still ok??

 

[45Auto]

Re: WATER PRESSURE Smartcraft reading

As long as the temperature stays normal you're OK. Normal temp means that the engine is getting sufficient water flow to remove the excess heat. If it were mine, I would run it while keeping an EXTREMELY close eye on the temp and shut it down IMMEDIATLY if the temp went above normal. Since most boats don't even have water pressure guages, you can ignore the low PSI readings if the temp stays normal. The pressure readings are definitely low though, and it would bug me till I found out why. My best WAG (wild a** guess) for now would be a bad sensor or plugged sensor port if it doesn't overheat.

Good Luck!

 

[pbuzz3323]

Re: WATER PRESSURE Smartcraft reading

After changing the risers and rehooking everything up im getting pressure at Idle of 1.2-1.7...speeding it up im getting 2.0...this still seems low to mewhere is the sending unit on a 2003 mercruiser with with seawater pump..S/N 624and up? Its not on the pump itself. Now my temp gauge reads 100degrees and doesnt move but its running fine with the new risers.

 

[Coors]

Re: WATER PRESSURE Smartcraft reading

My old 88 OMC water pressure is 12-15 over 2000 rpm; but new block and new drive; Any obstructions in yours? after verifying the above temp problem? You may have something stuck, maybe in thermostat area.