High Temp Alarm

[Abbe Normal 0]

Has anyone out there had the problem of the high temp alarm going off after 5-10 minutes of operating at wide open throttle? I have a 2006 270CR and continue to have this problem.

[The MOST 0]

Hello Abbe Normal,

 

The most common cause of overheating is a worn out or damaged impellor. Cherck your engine manual- I am certain that the recommended change out is every two years.

 

Sometimes small bits of debris (usually plastic or weeds) can get sucked into the intake and reduce or stop the flow of water.

[Solace 0]

Abbe Normal,

 

I had this problem last year but it did not matter what speed. My dealer replaced the impeller and it still overheated. After some searching they found small pebbles and vegetation inside the cooling system that had to be cleaned out. On my 2007 270 the thru hull fitting for the engine does not have any type of screen protecting it. I have called Monterey on it and asked what can be done but really did not get a good answer. I had asked about a sea strainer inline but the response was no due to water flow needed for the engine. I guess if I would have done it, it would of violated my engine warranty.

[Patrick 0]

I had this problem last year but it did not matter what speed. My dealer replaced the impeller and it still overheated. After some searching they found small pebbles and vegetation inside the cooling system that had to be cleaned out. On my 2007 270 the thru hull fitting for the engine does not have any type of screen protecting it. I have called Monterey on it and asked what can be done but really did not get a good answer. I had asked about a sea strainer inline but the response was no due to water flow needed for the engine. I guess if I would have done it, it would of violated my engine warranty.

Abbe Normal,

 

Two years ago I restored a 1995 Monterey 276 that was in bad shape, after two replacing power (new 4.3s) and outdrives on my shakedown cruise the port side 4.3 (from that date known as the bad twin) started to overheat. During my investigation to the cause of the overheating on this brand new equipment I learned a few things, one of those might apply here: The pebbles inside the engine could have cause damage to the water pump and could cause insufficient cooling of the engine. Also check the thermostat to make sure that a pebble isn’t keeping the thermostat closed. I am curious though. I may be showing my ignorance here but why is your engine cooled with a water source the come in from a through hull?

Finally the source of my own overheating was a defective impeller. The compound used to glue the impeller to the bearing was either misapplied or not there at all. It caused the impeller so work at low speeds (I assume because of friction) but that at high speeds the impeller would heat up and begin to slip so much that it did not move any water.

Hope my armature information helps.

 

-Pat Buchanan

[marfi 0]

Hi,

 

Just put my 278sc 2 days ago on the sea for the first time, just to tell you that the boat have a pomp on the bottom if the water stop comming from the sterndrive it will come from the bottom off the boat, so if it gets vegetables or a plastic, it won´t warm up, i it have a fresh water cooling system, with a new ECM.

 

Best Regards

 

Marfi

[Solace 0]

Patrick,

I am not for sure when this design cam into production but a few of my friends have the same except they have a half clam shell on the bottom with a screen. Maybe the MOST can fill in the rest.

 

[JRSto 0]

I drive a 2006 302CR (twin 5.7 DP Volvos) and I have experienced that problem many times in the past couple years. Try disconnecting the wire from the sending unit on the riser elbow. If the alarm stops sounding and your temperatures are normal ... you may want to change out the sensor. I carry a spare all the time for that very problem.

[Abbe Normal 0]

I just had the shop replace my water pump impeller. Parts of the impeller were missing. Fourth season of use. I should have changed it out every two years as recommended.

 

I drive a 2006 302CR (twin 5.7 DP Volvos) and I have experienced that problem many times in the past couple years. Try disconnecting the wire from the sending unit on the riser elbow. If the alarm stops sounding and your temperatures are normal ... you may want to change out the sensor. I carry a spare all the time for that very problem.

 

[munroe67 0]

I have an 01 282 with twin 4.3L V6 and Bravo IIIs. I had one motor which was heating up only on plane and I did the following to correct the problem

1.) Impellor and Thermostat are the first things to change

2.) Pull the inlet side of the cooling hose to the thermostat housing and start your motor breifly to see the water flow. Should be like a fire hose. This will tell you if the clog is in the motor or in the raw water entrance

3.) Clean the intake hols in the drive with a phillips head screw drive and then use a coat hanger to clean out any barnacles in the lowere drive housing. You have to get wet usually to do this. Use a hose to blow out the debris you create to keep it from entering your motor

4.) Work backwards from the hose in #2 to verify they are free from debris. Hose, PS Cooler Hose, Impellor pump Hose. Using a dock hose and back flushing is what cleared my blockage from the line leading from my transom to the pump.

 

you can get a great deal of info from touching the motor to see what parts are hot

TStat housing cool and risers hot = poor flow or bad risers

The water flow is usually drive to impellor to Tstat housing to circulator (water pump) to engine passages to thermostat to risers out through the exhaust

 

Just make sure that you are seeing 2 things

1.) That you are really heating up. If you touch the top of the riser and the Tstat housing and they are cool but you are getting an alarm it could be your sensor

2.) Some people may tell you to pull the thermostat and run it wide open but this is not a great idea just a quick fix that will get worse and usually screw up how the fuel is being atomized in the motor. Most boat motors run great around 170-175 (10 to 15 above the thermostat recommended) too cool is not good and can cause fouling and stalling and too hot can cause detonation and motor damage. A motor without a thermostat is apt to do anything since there is not control over the heating

 

Hope it helps

[298SS05_VA 0]

Hi All,

 

I have a 2005 (bought new in 2007) 298SS with dual MCM 350 MAG MPI Horizon engines with Bravo Three drives and only 107hrs.

My port engine (connected to hot water heater) is overheating and there is no water coming out of the exhaust exit.

From my understanding this is a Closed Cooling system that uses sea water to cool the anti-freeze (heat exchanger?).

I am early in my diagnosis and have only verified that the seacock is providing water to the seawater pump and the drive belt looks to be in excellent shape.

My next items to pursue is seawater pump (impeller check), thermostat, heat exchanger (wire brush?) and exhaust eldows.

Is this still the direction and order I should continue with or is there a better order for expected repair/clean/replacement?