Mercruiser 5.0LMPI 2008 SN:1A302029

[RonJNash]

Hi, I have the 2 beep every minute issue after the boat has come up to temperature. Temp Gauge showing 170 and stable. Always shows 0 - 170. I have today replaced the IAC and cleaned the inlet / butterfly area with carb cleaner, New IAC filter with no resolve. I noticed today that the Exhaust manifolds are very hot, too hot to touch, however, the Risers are cold. Stopping the Engine and then restarting, the beep continues every 1 minute or so following restart. Boat idles fine 600rpm and seems to perform OK, seems a bit loader than normal. My question is - "should the risers be cold when the manifolds are too hot to touch? what could be the cause of this issue?

Any help appreciated

Thanks

 

[Bt Doctur]

standard cooling or fresh water cooling, Alpha or Bravo drive

 

[RonJNash]

Sea Water Bravo Three. - Bravo Three just serviced and water passage cleaned etc.

 

[scoflaw]

Could be many things but hot manifold cold riser isn't 1 of them. Smart Craft ? what's flashing on the screen ? Low water pressure and low drive fluid are the most common. May need to get the ECM read

 

[RonJNash]

Thanks scofflaw, No Smart Craft. Drive Gear Lube good, just been changed. If I understand correctly, low Gear Lube ould cause a continuous alarm. Agree looks like I am going to have to have the ECM read, however, I also understand that soft alarms are not held in Freeze Frame memory and only show when unit connected and alarm activates (Real Time), is that correct?

Also if it were an overheat issue, is this also a continuous alarm tone?

Thanks

 

[scoflaw]

I believe you are correct with continuous alarm for the fluid and overheat. 555 ecm has many 2 beeps per's. So you need to take it for a ride with the scanner hooked up.

 

[RonJNash]

If it were low Water Pressure, is this a 2 beep alarm.

Would like to know if cold Risers with hot manifolds is normal, I am sure that the risers were hot in the past. May be poor water pressure?

 

[alldodge]

Your probably going to need the motor scanned to get the reason. There are 30+ faults which will cause a 2 beep alarm. If you have CAT's and/or digital controls the number goes higher

The most common cause is the water pressure switch, but the switch is expensive and its just a guess right now

 

[RonJNash]

Many thanks for the response's, I have engaged a marine engineer to take a look and read the ECM codes. Will update on his findings?

One question I still have: Is it normal for the risers to be cold , not even warm, while the Exhaust manifolds are too hot to touch?

 

[alldodge]

One question I still have: Is it normal for the risers to be cold , not even warm, while the Exhaust manifolds are too hot to touch?

Yes, if you have full closed cooling, which my guess is you do. You should have a round tube across the front of the motor with a radiator cap on top of it

 

[RonJNash]

Hi Alldodge, No its salt water cold. I am sure that the risers were hot in the past.

 

[alldodge]

Hi Alldodge, No its salt water cold. I am sure that the risers were hot in the past.

OK, raw water cooled.
In this case you need to remove the risers and look at the gaskets. See if the cooling channels are clear

Its also normal for the 2 beep to go to a solid alarm when the boat is throttled up on plane if its the water pressure switch

 

[RonJNash]

Update:

Had ECM scanned today - Water Pressure Sensor Code. Going to replace and hopefully no more beeping

Will update once fitted.

 

[scoflaw]

Chances are good you do have low water pressure and its not the sender. You should do a water volume test first.

 

[RonJNash]

HI ScoFlaw, I did ask this question, is it the sensor faulty or Low Water Pressure. I was advised the sensor, common fault. There are no overheating alerts / codes. When you say "Water Flow Test" is there a specific test or is it just remove a hose and check there is sufficient water flowing?. I also mentioned about the cold risers and very hot manifolds, however, he did not seem concerned and indicated this is normal.

 

[scoflaw]

So you have no water pressure gauge ? Someone can correct me if I'm wrong, the water volume test should produce 7 liters of water at 1000 rpm in 60 seconds

 

[RonJNash]

Many thanks for the replys.
No gauge for pressure If it were poor water pressure ue to blockage or impeller ect, would I not see an increase in temperature on the gauge and would there not be a continus beep? I think the cold risers I am concerned about May be nothing to be concerned about. I will see if the new sensor stops the 2 beeps every minute. Pressure sensor is posiioned on power steering cooler correct?

 

[alldodge]

Yes, power steering cooler