‘99 Sunsetter VLX Overheating Issue

[tmo166]

‘99 Sunsetter VLX Monsoon engine 

Sooo had an overheating issue last weekend. Cruising 30 mph and temp gauge shot up 230. Replaced thermostat (160 deg.) since I have no idea last time it was changed, checked impeller, checked for rubber in trans cooler, checked intake port on bottom of boat. Everything checked out good. Took it for a drive today and ran perfect for about 2 hrs then I sped up to about 40 mph and temp went to 230-240. Slowed down cut boat off waited a few and cranked up. Temp steady at 160 for next 20 minutes….any ideas what I’ve got going on???

[UWSkier]

check all your hose clamps to ensure you don't have any leaks anywhere.

Are you sure you're actually hitting 230 and aren't getting an erroneous reading?

[tmo166]

Checked all hoses with boat running don’t have any leaks. I’m not 100% sure the reading is accurate but last weekend the motor was hot enough I could hear water boiling inside the motor sooo I feel like it’s fairly accurate 

[Rednucleus]

Check the motor circulating pump (not the one pulling raw water) may have a failed bronze impeller 

[Steve B.]

If that motor uses a belt to drive the pumps check to make sure that is tight.

[tmo166]

31 minutes ago, Rednucleus said:

Check the motor circulating pump (not the one pulling raw water) may have a failed bronze impeller 

How do I check that?

[Rednucleus]

You will have to pull it off the front of the motor and there should be an inspection plate on the back to remove. Just like changing a water pump on a car. Here's a thred to review - 

 

Edited July 2, 2023 by Rednucleus

[csleaver]

It sounds like a problem with the belt driven water circulation pump.

[Bozboat]

Sure sounds like a bad circulation pump. 

[BlindSquirrel]

I concur. Pretty easy job, make sure you get the marine version. Might be worth getting a new belt too while you are in there. Just need to remove the impeller housing mount for belt replacement.

[tmo166]

Anybody point me in right direction of part I would need…I’m kinda confused and having a hard time googling the correct part?

[John I.]

https://www.bakesonline.com/quicksilver-circ-57-water-pmp.html

 

 

[tmo166]

19 hours ago, Rednucleus said:

You will have to pull it off the front of the motor and there should be an inspection plate on the back to remove. Just like changing a water pump on a car. Here's a thred to review - 

 

Took pump off. Is there anything that can prove the pump is bad? I’m not seeing anything that makes me think the pump is bad?

[BlindSquirrel]

5 minutes ago, tmo166 said:

Took pump off. Is there anything that can prove the pump is bad? I’m not seeing anything that makes me think the pump is bad?

Did you see any dry water trails below it? Any evidence that it was leaking? Does it spin easy and noise free?

[tmo166]

1 minute ago, BlindSquirrel said:

Did you see any dry water trails below it? Any evidence that it was leaking? Does it spin easy and noise free?

Spins easy and free, no signs of water out the weep hole or leaking

[BlindSquirrel]

20 minutes ago, tmo166 said:

Spins easy and free, no signs of water out the weep hole or leaking

Interesting…  other than the weep hole, obvious squeak, or impeller deformation … I’m not sure how else to tell it it’s bad.
Thinking of other things to check…. All the hoses look good? Verify the two that connect to the thermostat are good(both sides of the housing), mine have kinked themselves before. Pretty sure they are supposed to be formed, but mine were replaced with straight hose. Causing a pinch, especially when hot. 
Is your main intake hose original? The one from the vdrive to the impeller housing. Mine was okay looking on the outside, but nasty on the inside a few years ago. Kind of a stretch, but you must have a restriction somewhere if both your impellers are good.

You could take out the thermostat and drive without it to rule it out. Should get up to 160ish at idle and 100ish while driving. Mine was like that for several years till I looked to see why the temps fluctuated.

[Bozboat]

1 hour ago, tmo166 said:

Took pump off. Is there anything that can prove the pump is bad? I’m not seeing anything that makes me think the pump is bad?

Shake it like a shake weight

does it rattle?

or take the plate off the back and look at it

Edited July 2, 2023 by Bozboat

[tmo166]

1 hour ago, Bozboat said:

Shake it like a shake weight

does it rattle?

or take the plate off the back and look at it

I took plate off back. It’s not cracked and I can see blades spin ???

[Bozboat]

24 minutes ago, tmo166 said:

I took plate off back. It’s not cracked and I can see blades spin ???

Is the impeller attached to the pulley? Sounds like I may have sent you down a rabbit hole.  I was sure your circ pump was the problem 🤷🏻‍♂️

[justgary]

On 7/1/2023 at 3:11 PM, tmo166 said:

Checked all hoses with boat running don’t have any leaks.

Pull all of the hoses from the hull fitting to the raw water pump and inspect them.  Carefully seat them when you reinstall them and make sure the clamps are tight.

Any leak in the intake (suction) side will suck air, not leak water.  It doesn't take much of a leak to quit pumping water.

[csleaver]

It may be worthwhile to do a compression test (or leak down test) to see if combustion gasses are getting into the cooling system. 

[UWSkier]

Oil looks good?

[tmo166]

7 minutes ago, UWSkier said:

Oil looks good?

Yep looks like normal and at full mark

[Steve B.]

Following up, you've replaced the circulating pump at this point? And if so, what is happening temp wise now.

Steve B.

[tmo166]

6 hours ago, Steve B. said:

Following up, you've replaced the circulating pump at this point? And if so, what is happening temp wise now.

Steve B.

I took circulating pump off, got a new one on the way…doesn’t seem to be anything wrong with it but not sure