Over heating problems1985 AQ225

[gary8u]

I have a 1985 Volvo AQ225D with a Volvo 280 out drive. I've changed the impeller & thermostat. When I take the impeller housing cover off it is wet in side but when I take the hose off at the thermostat housing there is no water coming out. So I guess I have a blockage? Whats the best way to clear it? Or do I have other problems. Any suggestions would be helpful. Thanks

 

[sixlegfish]

Re: Over heating problems

Try back flushing it from the thermostat housing.

 

[RicardoMarine]

Re: Over heating problems

Follow the sea water path, and you will likely find an air suction leak UP Stream of the crankshaft pump..... or a restriction after the sea water pump.

One tiny tiny suction leak can kill the entire system.

Check the following path:

• pick up grate in lower unit
• lower pivot tube O-ring
• water neck fitting corrosion and/or bad special "beaded gasket" under the water neck fitting
• excessive play at top pivot tube bushing (the beaded gasket cannot seal if the bushing is shot)
• a compromised suction hose or connection
• worn thrust surfaces within the crankshaft pump body (rear surface/front cover)
• worn impeller cam
• sometimes a NEW impeller against worn thrust surfaces
• restriction in the exhaust spent sea water ports... often these can be cleaned out

last, but important on this system "Short Riser-to-Y-pipe coupler hoses"
If the coupling hoses are too short (as they often are) one of them is inadvertently clamped over the "scalloped" section where the spent sea water is intended to enter the exhaust flow. (look at your risers, you'll see what I mean)
When the hose is compressed into the scallops, it eventually collapses into the scallops, and restricts sea water flow.
The cure is to purchase NEW coupler hoses, but by the foot so you can increase the length and move the band clamps UP the riser.... not over the scallops!
You will have to trust me on this...... I see this often!

Follow the path.... you'll find it!

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