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Volvo penta over heating

Yes i did twice the first one was suppose to be a spare was told and looked new in the box when overheated again i replaced it with a new volvo thermostat
 
Yes i did twice the first time with a spare that came with the boat and when over heated bought a new one and changed it checked the first one i put in and it worked ok so ill keep it as a spare
 
You very likely have a restriction or a suction breach within the seawater side of the system.

I will suggest that you stop wasting you time doing things that have not been productive!
Roll up your sleeves and dig in.

Start at the stern drive and work your way forward.
Leave NO stone un-turned.

Do this, and you will find the issue!
 
Yes i did i started from the stern and checked for loose clamps and made sure all bolts were tight i even tried using a mechanics stethoscope at each connection to hear for any noise or sounds that indicate it sucking air and checked to see if there is any water dripping but i did not find anything . i have replaced everything except the copper pipes and the pivot tube and seals all the gaskets , orings and gromets that fit over the end of the pipe were replaced
 
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fishgurru said:
Yes i did i started from the stern and checked for loose clamps and made sure all bolts were tight i even tried using a mechanics stethoscope at each connection to hear for any noise or sounds that indicate it sucking air and checked to see if there is any water dripping but i did not find anything . i have replaced everything except the copper pipes and the pivot tube and seals all the gaskets , orings and gromets that fit over the end of the pipe were replaced
Click to expand...

When testing for a pressure leak, use pressure.
When testing for a vacuum or suction leak, use vacuum or suction.


For the suction side of your seawater system (from the seawater pump back to the stern drive), you can give this a try:

1.... disconnect the suction line from the pump.
2.... place your wet-vac suction hose on this side of the suction line. (use tape to ensure a good seal)
3.... tape off the seawater inlet area on the stern drive. Be sure to include the weep-hole.
4.... at any/all potential areas where a suction breach could occur, squirt some shaving cream around the area.
Yes..... that is correct.... Shaving Cream!

That includes the:
pivot tube lower O-ring area
water neck fitting area
S hose and S hose connecting points
chrome tube connections
copper tube to rubber suction hose connections

If there is a suction breach, the shave cream will disappear at that area.

Effectively, this is the reverse of using a soapy solution to check for pressure leaks (air bubbles at the leak).


.

 
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fishgurru said:
How can you tell if the circulation pump is working properly
Click to expand...

You would need to remove it and take a look.
The pulley's mounting hub must be secured to the shaft.
The shaft must be secured to the impeller.
Bearings/seals must be good, although if bad it may not prevent pumping action.
The impeller blades must in tact.

In this image, we are looking at the AFT end of the impeller wheel.
You cannot easily see the impeller blades.
The blades are on the FWD side of the impeller wheel.

AQ 125 circ pump.jpg
 
I have an "engine watchdog' sender on the thermostat holder and this runs at about 82C ( ? 180F) on my AQ151. Have an alarm at 85C (185F) that beeps and flashes but since I cleaned up the engine a few years back this is just a backup - don't trust my old volvo gauge which may need a new sender or instrument - will get around to replacing both sometime.
 
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