Overheating alarm on SeaRay Sundeck 200

mpickard

New Member
Aug 14, 2012
2
East Coast
Boat Info
2010 Sundeck
Engines
5.0
Overheating alarm on SeaRay Sundeck 220

I have 2010 SeaRay Sundeck 220 with a 5.0L MPI Engine. I keep going into an over temperature alarm when I am running 3,000 RPM and above. The alarm does not occur when operating under 3,000 RPM. Everything seems to check out fine. My water pressure is 16.4 psi, my H20 Pressure is 12.9 psi and my engine operating temperature never get above 165 degree's. It normally is between 156-160 degree's when it goes into over temperature alarm and puts the boat into "limp" or "safety" mode. Returning to throttle to neutral for only a few seconds clears the alarm. I can then operate the boat in a non alarm condition until I hit 3,000 RPM's or above and then I get the over temperature alarm typically in less than a minute. All of the engines components are original. Water pump impeller has been replaced 2xs. Bought is serviced by the book every year. Had it to a certified Mercruiser repair facility and they found nothing wrong. Probably because they did not do what I told them to do...operate the boat over 3,000 RPM's and wait for the alarm. Heading on vacation on 7/21 and want to get my boat running. I am mechanically inclined and can pretty much do anything. Just need help trouble shooting this problem. Temperature sensor? I say no because my operating temperature is in normal range. Exhaust manifolds and risers? Maybe...they are 7 years old but my pressures seem normal....lost.
 
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Does your boat have a Bravo III outdrive? If so, I'll bet you a nickel you are at the early stages of bravoitis. It's fairly easy to check. Follow the water inlet hose from the inlet of your seawater pump to the transom plate of the outdrive. It connects to a water inlet housing with 2 bolts holding it to the transom plate. The water hose should have a quick connector with a wire clip holding it in place. Use a regular screwdriver under the clip and give it a twist to pop the clip out about 1/4". You should be able to pull the hose off of it. Remove the 2 bolts, and take a look under it where the rubber hose comes through. If you've got it, you'll see if right away.

Check out this thread: http://clubsearay.com/showthread.ph...o-Smartcraft-output/page3?highlight=bravoitis

Post #58 Has a picture and #59 has a cell phone video.

At 3,000 RPM and below the pump is able to supply enough volume of water to cool your engine. Above 3,000 RPM, the water pump can't get enough water so the impeller starts to cavitate. It makes air bubbles, which get to the sensor and that sets off the alarm.
 
Re: Overheating alarm on SeaRay Sundeck 220

Good call Skibum. I did have bravoitis this past year. Very low water psi at higher rpm's. I had it fixed. It wasn't easy. They literally had to pull my entire engine out to get to the area. Was just too tight. There is an upgrade kit that apparently helps prevent this from occurring again. When I had bravotis the alarm was "Low Water Pressure" not "Over Temperature Engine" like I am experiencing now. I have really good psi readings at high rpm's. water pressure is at 16 psi and H20 pressure is 14. Don't know the difference between the 2 but my gauges read both. In talking to a mechanic at Marine Max in Baltimore he said he thinks my pressures are too high which could mean some type of an exhaust restriction somewhere. He said it sounds like I am bringing plenty of water in but maybe not exhausting enough which could cause higher than normal pressures. I have a premium Mercruiser repair facility putting a computer on it this morning to see if we can't narrow down the problem to a more specific area. Thanks for the feedback. That was an excellent thought but I have already been there and done that.
 
I have a 2003 sundeck 220. 6.2 mercruiser. replaced the raw water pump impeller and thermostat. still overheats. replaced the manifolds and risers. still overheats. replaced engine circulating pump. still overheats. the new pump was noisey so I replaced it again. still overheats. took out the thermostat. still overheats. the water inlet holes in the lower unit are clear. any ideas??? help!!!
 
You mentioned lots of parts replaced, but no mention of the raw water inlet through the transom.

That would be the next thing to check. It is very difficult to access on some boats.
 
Most systems have 2 sensors for the water temp. 1 for the gauge and 1 for the ECM.
Have you checked it with an IR gun ? 16 psi at speed is normal.
 
I have a 2003 sundeck 220. 6.2 mercruiser. replaced the raw water pump impeller and thermostat. still overheats. replaced the manifolds and risers. still overheats. replaced engine circulating pump. still overheats. the new pump was noisey so I replaced it again. still overheats. took out the thermostat. still overheats. the water inlet holes in the lower unit are clear. any ideas??? help!!!

i have a 6.2.. did the same.. found a piece of broken imellar wedged in the fuel cooler exchanger after the raw pump for original owner servicing..didnt go look for the broken piece i guess... runs great now..
 
Most systems have 2 sensors for the water temp. 1 for the gauge and 1 for the ECM.
Have you checked it with an IR gun ? 16 psi at speed is normal.


Excellent advice. Hook a Rinda and determine what the PCM is seeing. Yes 16 psi is normal!!!!
 
Yes 16 psi is normal!!!!

what is normal ? i have about 3 psi waterpressure at my 5.0 mpi and a buddy with the same engine has the same reading without any alarm or overheating . ( bravo 3 drive )

16 psi sounds like you have a restriction after the sensor and the engine struggels to freely pump the water out again , so little circulation of water thru the block and instead buildup of backpressure .
 
at idle 1.5 to 3.0 psig is normal. At 3K rpm above anything between 10-18 psig. My dash gauge shows 175F while my Rinda shows 158F. My buddies Rinker showed 180F on dash and his PCM saw 160F. Dash gauges are useless. Boat has 160F thermostat. Thermostats fully open at their temperature setting but don't fully close until about 5-10F below their set temperature.
 
I have a 2003 sundeck 220. 6.2 mercruiser. replaced the raw water pump impeller and thermostat. still overheats. replaced the manifolds and risers. still overheats. replaced engine circulating pump. still overheats. the new pump was noisey so I replaced it again. still overheats. took out the thermostat. still overheats. the water inlet holes in the lower unit are clear. any ideas??? help!!!

You've replaced a LOT of parts, but what diagnosis did you do to warrant that replacement? Do you get an alarm, does the gauge read high, or both? When it was overheating, did you feel the top of the elbows with your hand? Was there ANY scoring in the impeller housing? Did you do the impeller water flow test? Are you salt or fresh? You likely have a B3 drive (but confirm) so bravoitis is a possiblity. Hindsight, of course, is 20/20, but it would be well worth the hour of labor to have a pro look at it with a scanner. All of these things I've mentioned (and others) can be explained in more detail, but please do a search for them as they have been discussed many times. It will save us the time of replying over and over and over.
 
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