High temp warning

rasbury

Working through a cooling issue...I have a bravo III/350 set up, 2005. I have a water temp sensor at the thermostat on my 1/2 fresh water cooled system and what appears to be a water pressure sensor on the power steering cooler. If I have the audible high temp go off, I assume that is on the closed loop side of the system and not the raw water which appears to only have a pressure sensor....is there any gauge or anything for that I'm missing?

TikiHut2

My old brass RWP was replaced with new brass RWP(complete w imp).

I admit I lost track of this one so I guess I missed the part where the belt broke on a start. Was the RWP seized up? If not, did u determine that it wasn't the RWP and find why it broke?

>>So there's ENORMOUS flow from the output side of the RWP with the hose temporarily removed when the engine is briefly run on the muffs???

TGM

rowboat212

Your belt broke?  

You may have a seized or about to seize engine circulation pump.  

The dash gauge is your engine temp.  There are audible alarms for both.  Your engine circulation pump ain't pumping your risers, it's pumping through your block and exchange... That's all the circulation needed on a closed system.  Your thermostat controls the volume of flow through block and has notta to do with risers.   Your raw water pump is what pumps the risers... 

If your dash gauge is reading hot, then it's the closed system.  

MarkB

Tiki your Canadian friends will be in your playground in just over 2 weeks. 

TikiHut2

Diagnosing this is extremely frustrating with only fragments of the story and multiple threads on the same topic and 212 is dead on target.

If the RWP siezed it was the problem (and possibly the engine pump too). Obviously the next thing in-line is simply replacing a properly tested thermostat. The engine water pump is the 3rd part of the system followed by blockages in the lines >> manifolds and headers. Have you confirmed any overheat warnings with an IR temp gauge too? Good luck I'm moving on.

Mark, there's always room for another snowbird. You and the family need to get a family boat to keep down here. Cya soon. MnK

rowboat212

rasbury said:

thanks 212, so it sounds like my raw water pump, even with the scoring may be ok after all. I would assume if the engine circulation pump were bad, like a car, it would be leaking water if the bearing were bad or otherwise if seized would be making a heck of a noise which it is not. I will test the new therm. and put in this weekend and see where I'm at!

Thanks,

That bearing squeels like a demon because of the fan... That heavy clutch fan is what breaks the seal and wears the bearing... Your floater ain't got one.... It does have a paddle, though, and that paddle can and will wear to nothing over time and never give a hint it's bad except for reduced flow... Google pictures of worn engine water pumps for what I'm talking about... You're likely to have an ah-ha moment. 

Black_Diamond

Good comment 212 (aka xxxxxxx) lol  The engine circulation pump vanes can and do wear/corrode away leaving you with little to move the coolant.  Too much belt tension is another killer of the belt drive accessories too.  You can over tension a belt..few people have the tools or bother to do it right and just use a prybar to make it a guitar string.  Ultrasonic tensioners are the best.

luckydog

ras, Good-luck hope it does the trick for you, I'll have my wife do an Indian dance for you to make sure it fixes it once and for all

rowboat212

The temp of the exhaust manifolds has no value to fuel and spark management, so the PCM/ECU could care less about its temp... It cares greatly, though, that there is flow... The temp of the engine is of vital importance for managing its function. 

rasbury

If there is a sensor there, what reads it? I can't imagine it would be tied to the audible or dash gauge, but it has to go somewhere!

JC290

Bet it goes to the audible alarm 

rasbury

ah, did not think of that...so the one on the steering cooler goes to the audible and the one on the thermostat goes to the gauge or the other way around?

JC290

Thermostat one goes to gauge I think cant remember 

rasbury

Yep Yan, will do that but was hoping for the short cut! I had to order a new thermostat, it was marked 170 but I have a hard time thinking it had ever been changed....it was not opening as near as I can tell until around 180. Then, if I'm still running hot I would have to assume the raw water pump is not getting enough water to the heat exchanger to cool and will then have to either replace or try to rebuild the pump. I really like the idea of the pump I posted in another thread which was the OEM pump with a wear plate on both ends and a slightly "shorter" impeller so that the pump could be "rebuilt" multiple times, at least until the bearing failed. If my boat truly has 100 hours on it like the hour meter states, then these pumps are really crap! I want to spend time around sand bars and islands so if this exposure to sand is going to eat up the pump like this one appears to be, I need a cheaper solution than a new pump every year....

JC290

Ras from what I read in your other post I believe the thermostat will cure your problem if not send me a plane ticket and I will help lol 

rasbury

I do have a sea strainer on the inlet hose so I'm pretty confident I don't have anything plugging any lines, thank God for that! If the thermostat does not solve the problem then I'm back to the water pump, perhaps when it got hot from the impeller issue if messed up the thermostat. It is just so puzzling that I did not have any issues on either side until the the impeller failed and now have issues....I will figure this out, to poor to take it to a shop until I exhaust these possibilities I can fix myself....

Stodge

I've had more problems the other way, with a thermostat stuck open.  I've assumed that's an effect of lake water flowing through the cooling system of the motors.

rowboat212

Stodge said:

I've had more problems the other way, with a thermostat stuck open.  I've assumed that's an effect of lake water flowing through the cooling system of the motors.

The fail safe 'stats do that.... I'd MUCH rather have them fail open than fail closed.. as a precaution on any 'stat, though, not only do I test them prior to install several full cycles, but I also drill two opposing tiny holes in the blades (if they don't already have them; manufacturers caught on quick to that trick).  this allows flow if something crazy like a broken spring set breaks, as some water will flow, which may be the difference in limping home or radioing help. 

MarkB

Great idea 212rowboat!

rasbury

Yes, I've heard that row but never figured enough water would run through the little holes to make a difference......really?

rowboat212

rasbury said:

Yes, I've heard that row but never figured enough water would run through the little holes to make a difference......really?

It'll run hot at idle but not overheat... Trick is idle.. It takes slightly longer to open due to the flow prior, but allows slower heating of block and heads which are kinder to gaskets and mating surfaces... Which doesn't give you permission to jump in the boat and hammer the throttle on a cold engine, possibly flash boiling the juice in the block, but gives you more latitude in those circumstances. 

frenchship

Rowboat,
What size  hole would yo suggest.....

rowboat212

No bigger than a quarter inch... I think I drilled a 3/16, but I think I popped three, too. 

rasbury

you for sure have to have a therm in these motors for them to run the right temp. Keep in mind they don't just open and their job is done- they constantly open and close depending on eng temp so ya got to have it.

rowboat212

With efi it HAS to exist.. spark timing and fuel trim depend on consistent operating temps.   Old carbs point sparked? Not so much... Needle them rich, around 13.5:1, and let her rip... As long as it isn't forced induction, that is... It wouldn't be smart to lean out an engine at high turns with expensive parts. 

rasbury

if you drilled a couple 1/4" holes in mine, you would not have much left! That would decrease the surface area when closed by probably 50%. Picking up the new one today, hope to try it this weekend...ba hum bug!

TikiHut2

OMG this is Deja vu all over again! How can this one still be an issue? That sensor on the steering ram is for the water cooled ram.

Once again....... tried that thermostat idea when mine was at your stage Ras. DID YOU TRY THIS?? >>>>>> If water will freely flow from the foot intake with muffs on, to the point it attaches at the raw water pump intake......AND it WON'T flow when cranking the key (with the input reattached) and output hose detached AND your raw wtr pump looks like mine did......then replace the W_____P____. (Fill in the blanks)

Pics taken 18mths ago after somebody here mentioned tiny holes would prevent a problem with no flow. It didn't fix my need to replace the raw water pump. Good luck.
Mike
 Let's review:
pic#1 unacceptable wear that I considered barely discernible but it prevented prime even with all the vanes intact but I remained in denial (sound familiar?).



Pic#2 Tried tiny holes in thermostat to no avail.


ENORMOUS stroke of bad luck. I got defective OEM merc impellors from quiet recall.
CONFUSING THE MESS BUT STILL NOT THE PROBLEM!!



The eventual fix..... a COMPLETELY NEW RAW WATER PUMP as a few others on RBOC tried to explain to me too. Puller borrowed from auto parts store. NEW pump in place in 15mins, it was pumping water perfectly. END OF SAGA. Almost 100% sure it will be yours too when you finally surrender to the obvious like I eventually did. Aside from blockage and an easy test of the pump(above) it'll be over soon.

MarkB

Tiki is the Grand Master. 

TikiHut2

Hope my frozen Canadian friends are well. In honor of my new title I magnanimously concede all frozen northern territories and waterways to my loyal followers found north of the 49th parallel (or was that the 38th parallel ? Take that up with Kim Il) to be divided among themselves.

PS. Bribes and trinkets may be left at my front door.

rasbury

Well...I do have water flow which keeps me trying every possibility before I through in the inevitable towel.... I'm just not sure I have enough. Tiki I have two cooling systems- one raw water that cools the manifolds and the heat exchanger and  the closed cooling section that does the block. Now then, Grand Master, I do have water going through the manifold and comes out the back of the motor and it seems to be sucking up every bit of water that the hose can supply. That is why I was trying to figure out if the gauge was for the manifold temp or the block. And ditto for the high temp alarm which I still do not have a clear cut answer on. I pulled the thermostat which is a 170 degree item (the new one is as well even though the books states it should be 160) and tested it with the hand held laser and it does not start to open until 180 and does not fully open until over 200 right at boiling. So, I bought the new therm and will try that as again, I do have water flow. I'm just not sure I have enough water flow. If the new therm does not solve it than yes, I will throw out the towel. Got any extra of those towels????

rasbury

ps- your pump looks like the composite style while mine in the brass....

rasbury

and your inlet size on your therm is much smaller...Marine Max ordered me one like that but found the one for mine on the shelf after all....

rasbury

with regard to the questions above about the alarms, the belt broke just about as soon as I started it and backed it off the trailer. There was no audible alarm until it was hot. I wonder what the sensor on the cooler would go to then? I'll have to go through the book and see if I can figure it out.....if an audible alarm were to go off because of flow, it would have sounded as soon as the belt broke and water pump seized as there was no flow after than....does not make sense that it goes no where....

rasbury

well, there is enormous draw of the water and it does flow thru the manifolds and out the transom. I'm replacing the thermostat on the closed side as it seems that might have been bad. Raw water pump seized, broke the belt. All pieces of the impeller were right there in the pump. I just don't know if I have enough flow to cool, or, the therm went bad.....