Help with overheating problems

[edgpr]

Hi, I put the boat in the water today and it started overheating right at the dock. I went back home and try running it with water and this is what i get. If I put my water hose straight into the inlet for the engine water pump, the boat runs fine, no overheating. But if I try running it with the muffs, it overheats. I'm guessing is not my water pump, but my outdrive...but I don'tknow much about this. Engine is a volvo penta 5.0 and the outdrive im not sure of the model 280 or 290. Any help will be appreciated. Thank you.

 

[Bondo]

Re: Help with overheating problems

If I put my water hose straight into the inlet for the engine water pump,

Ayuh,... Being a Volvo, I imagine it has a motor mounted Raw Water Pump....
Pull it, 'n change out it's impeller...
Not the circulating pump, the raw water pump...
You don't say Which 1 yer messin' with...

Other than that, you might have an air leak in the suction line coming up through the drive somewhere...

 

[edgpr]

Re: Help with overheating problems

Ayuh,... Being a Volvo, I imagine it has a motor mounted Raw Water Pump....
Pull it, 'n change out it's impeller...
Not the circulating pump, the raw water pump...
You don't say Which 1 yer messin' with...

Other than that, you might have an air leak in the suction line coming up through the drive somewhere...

Yes, it has an engine mounted pump. I thought there was only one pump on the engine, which one is the RAW vs circulating pump? it's an '83. Tx.

 

[QC]

Re: Help with overheating problems

The pump that is belt driven is the circulating pump and will look just like an automotive pump. It circulates water within the engine. The one mounted on the front of the crankshaft is the raw water pump and sucks water out of the lake/river/ocean and provides the circulating pump with cool water to replace the hotwater building within your engine as it circulates. Hot water needs to go away, cool water needs to replace that which is dumped out via the exhaust. The rate of this hot water vs. cool water exchange is regulated by the Temperature Regulator, otherwise known as a Thermostat . . .

 

[Don S]

Re: Help with overheating problems

It's really hard to tell you which pump is which when we don't even know what engine you have. Some Volvos have both a belt drive circulation pump and a belt driven raw water pump. Can you post a picture of your engine and drive? Especially the front of the engine. This pic should give you an idea of which is which in the pumps.

 

[edgpr]

Re: Help with overheating problems

Yes, mine looks like the picture you put. Then I was putting my water hose going into the RAW water pump, not the circulating pump. So what does this mean? which one is bad, raw?

 

[86 century]

Re: Help with overheating problems

The impeller in the raw water pump is a wearing item most likely your problem.

 

[edgpr]

Re: Help with overheating problems

Ok. I took out the impeller from the raw pump...is this what is supposed to look like??

 

[Bondo]

Re: Help with overheating problems

Ayuh,... It's supposed to look like that, without the scratches, 'n gouges in it...
Clean up the housing, 'n replace the impeller...
Is the end cover scored up, if so, change it too....

 

[RogersJetboat454]

Re: Help with overheating problems

Ok. I took out the impeller from the raw pump...is this what is supposed to look like??

edgpr,

That looks like a worn out impeller to me. See how the veins look like they're deformed in the direction of rotation? Also have some good gouges on the edges where they would contact the cover to the pump. Is the cover all gouged up? That pump definitely looks like shes been around a long time. How does the shaft feel when you spin it (impeller removed)? Any leaks from the pump other wise?

 

[edgpr]

Re: Help with overheating problems

if feels rough, with some resistance when i spin it. the cover is in the same conditions as everything else there. I guess I will replace it and see if this fixes the problem.
I see some minor leakage but i believe is coming from the circulating water pump. Is this normal?

 

[Bondo]

Re: Help with overheating problems

I see some minor leakage but i believe is coming from the circulating water pump. Is this normal?

Nope,... There shouldn't be Any leaks....

 

[Don S]

Re: Help with overheating problems

Remove the impeller from the pump body, then turn the pump and see how the bearings feel.
I would bet when you take the impeller out, that the vanes will not straighten out. They should. If they don't straighten out, the pump doesn't pump.
Also, if the seal and bearings are bad in the pump, then it will not draw water up from the outdrive pickup because it's sucking air. Same with the cover gasket. If the pump sucks air, it will not suck water up from the drive.

 

[edgpr]

Re: Help with overheating problems

yeap, took the impeller out and the pump feels very loose, i don't think there is even any bearings left in there. I had to order the whole part, not just the impeller. Pricey guy, $220. Arrives tomorrow. Hopelly this will fix the problem. Tx for all the help guys.