bill_griffiths
Member
"I've just about exhausted
"I've just about exhausted every avenue in my quest to cure the overheating on my AQ225D.
The story is as follows:-
On the way back to port from a six hour cruise, we were two hours from home when we heard a 'bang' in the engine compartment and lost steering control.
We were in very rough seas and it was difficult to stand up let alone investigate under the engine cover. I realised that I had steering, but it was VERY heavy. I made the assumption that the power steering belt had snapped and nursed her back to the marina. On lifting the engine cover, the shaft of the main circulating water pump had sheared therefore throwing both belts.
I ordered a new water pump at great expense and fitted it the following weekend. Ever since then she has been overheating. I checked the impellor in the raw water pump and it looked ok. I removed the thermostat and checked it, it was fine. I removed the hose from the outlet of the raw water pump and started the motor, there seemed to be a good flow of water.
My conclusion was that the exhaust headers or risers were blocked therefore not allowing circulation. I ordered new riser gaskets and pulled the risers last weekend - they are quite clear with very little corrosion.
Before I left the boat, I disconnected the two 1" pipes that go from the thermostat housing to the exhaust headers. I connected a length of pipe to each of the outlets and hung them overboard.
When I started the engine, there did not seem to be as much flow as I would have expected, If I lift one of the pipes higher than the other it flows nothing at all and all flow goes to the lower pipe.
Should I have a real good flow into these pipes?
I am now back to suspecting the raw water pump.
Incedentally, the motor is running sweet, starts easily, idles fine and accelerates with no hesitation.
Any ideas on anything I've missed would be greatly appreciated.
Bill"
"I've just about exhausted every avenue in my quest to cure the overheating on my AQ225D.
The story is as follows:-
On the way back to port from a six hour cruise, we were two hours from home when we heard a 'bang' in the engine compartment and lost steering control.
We were in very rough seas and it was difficult to stand up let alone investigate under the engine cover. I realised that I had steering, but it was VERY heavy. I made the assumption that the power steering belt had snapped and nursed her back to the marina. On lifting the engine cover, the shaft of the main circulating water pump had sheared therefore throwing both belts.
I ordered a new water pump at great expense and fitted it the following weekend. Ever since then she has been overheating. I checked the impellor in the raw water pump and it looked ok. I removed the thermostat and checked it, it was fine. I removed the hose from the outlet of the raw water pump and started the motor, there seemed to be a good flow of water.
My conclusion was that the exhaust headers or risers were blocked therefore not allowing circulation. I ordered new riser gaskets and pulled the risers last weekend - they are quite clear with very little corrosion.
Before I left the boat, I disconnected the two 1" pipes that go from the thermostat housing to the exhaust headers. I connected a length of pipe to each of the outlets and hung them overboard.
When I started the engine, there did not seem to be as much flow as I would have expected, If I lift one of the pipes higher than the other it flows nothing at all and all flow goes to the lower pipe.
Should I have a real good flow into these pipes?
I am now back to suspecting the raw water pump.
Incedentally, the motor is running sweet, starts easily, idles fine and accelerates with no hesitation.
Any ideas on anything I've missed would be greatly appreciated.
Bill"