Volvo Penta 5.7 gxi overheating

[Nitetymme]

Are you sure all the ports in your stat housing are open? Including the bypass?
PS the impeller will never pull water from a tub . The water level would have to be nearly up to the top of the drive. You need hydrostatic pressure to fill all the passages in the drive and the full length of that hose that goes to the stat housing. Are you sure about how the hoses are hooked up to the impeller housing?

I assume all ports to the stat are open since it works fine with the hose connected to the engine.

 

[Lou C]

Good water muffs should be fine just make sure they fit well

 

[Nashville]

Yes, the hoses that attach to the impeller housing are of two different sizes so impossible to make the wrong connection. I was wondering if the pump could draw water from a tub of water. OK, that was my mistake thinking it could.

I pulled the impeller and although it did not seem damaged, i measured it and it's diameter was 2 3/16". The diameter of the original impeller and also the new one I have replaced it with measure 2 5/16". Don't know if that makes a difference. Also, the reason I replaced the pump housing was I noticed the old one had slight grooves worn into it.

I visually checked the hose from the pump back to the drive pickup and have not detected any holes or cracks. I attached water hose to engine connection and water flows back out the drive pickup.

Now that I have a new impeller installed, detected no leaks in the system, what is the best way to test it? Will attaching flush attachment to outdrive do it or do I need to get it to the lake?

The smaller diameter won’t seal against the I.D. of the pump housing. No seal, reduced/no flow. Muffs or lake to test.

 

[Lubak572]

The smaller diameter won’t seal against the I.D. of the pump housing. No seal, reduced/no flow. Muffs or lake to test.

So what was the verdict? Having same issue. I suspect drive as I had opened mine up, but I replace water tube, nipple, grommets, seals etc. I changed all lower seals on that drive. Hopefully I did it correct

 

[Nitetymme]

It appears my problem has been solved. After replacing the impeller (for the 3rd time), attaching muffs to the outdrive, water is flowing as it should and engine is cooling. I believe the impeller that was supplied with the pump unit was the incorrect one. It was 2/16 inch small in diameter. Just a guess. Thanks for all your help. Off to the lake I go!!!

 

[Lou C]

Glad you got it and it was a simple solution

 

[bruceb58]

Thankfully, you didn't go and split the drive.

 

[BRICH1260]

Yes, the hoses that attach to the impeller housing are of two different sizes so impossible to make the wrong connection. I was wondering if the pump could draw water from a tub of water. OK, that was my mistake thinking it could.

I pulled the impeller and although it did not seem damaged, i measured it and it's diameter was 2 3/16". The diameter of the original impeller and also the new one I have replaced it with measure 2 5/16". Don't know if that makes a difference. Also, the reason I replaced the pump housing was I noticed the old one had slight grooves worn into it.

I visually checked the hose from the pump back to the drive pickup and have not detected any holes or cracks. I attached water hose to engine connection and water flows back out the drive pickup.

Now that I have a new impeller installed, detected no leaks in the system, what is the best way to test it? Will attaching flush attachment to outdrive do it or do I need to get it to the lake?

I would try running on muffs before going to the lake, if it works, then take it to the lake. But you might first prime the pump via the blue flush port, then try the muffs. Make sure your blue flush port cap is on tight before you run on the muffs.