volvo AQ125B overheating while on plane

[barmahn]

I have been fighting this problem for a little while now. I have replaced the fresh water pump and housing, thermostat, flushed heat ex changer out and it still over heats. When I use muffs to supply water to motor it wont pick the water up. But if I put the boat in the water it will pick the water up with the fresh water pump. It will run fine for a little while on plane and then it will start to over heat. Slow down to Idle and it will run and stay cool. But as soon as i try and get it on plane again it starts to overheat. I am sure I am losing water on the fresh water pump to help cool it down. The closed system with the anti freeze in it is full and did a psi test and it doesn't drop any psi. Any help would be great. Do I need to replace the hose inlet on the outdrive? all the hoses seem to be ok and no signs of leaks anywhere on the fresh water system. I can dump water down the heat ex changer and it will go out the lower unit like it should.

 

[kenny nunez]

Look at the aluminum nipple that feeds water to the transom plate via the rubber hose. It is easy to change with a Allen wrench and a screwdriver with some patience.
The other thing if the problem persists will be the “O”ring that seals the lower gear housing to the suspension fork. Tilt drive up. Remove the shift linkage cover, drain the oil and with some more Allen wrenches drop it down. There is another “O”ring that seals the oil cavity.
Volvos AQs are the easiest to work on and the tools needed are fractional not metric like the engine.
Try to get a Volvo service and parts manual for the engine and drive.

 

[Fun Times]

+ 1 with kenny nunez as he has you heading in the right direction.

Do I need to replace the hose inlet on the outdrive?

Most likely as it fits the most common description.

Here would be your parts catalog which helps as it covers both the engine and drive for these models,
Marine Gasoline Engines for AQ125B - 7744630 - volvopentastore.com

Transmissions - 7744630 - volvopentastore.com

 

[Scott Danforth]

that little pot metal fitting lasts about 4 years in fresh water and about 18 months in salt water (even with flushing).

 

[barmahn]

Look at the aluminum nipple that feeds water to the transom plate via the rubber hose. It is easy to change with a Allen wrench and a screwdriver with some patience.
The other thing if the problem persists will be the “O”ring that seals the lower gear housing to the suspension fork. Tilt drive up. Remove the shift linkage cover, drain the oil and with some more Allen wrenches drop it down. There is another “O”ring that seals the oil cavity.
Volvos AQs are the easiest to work on and the tools needed are fractional not metric like the engine.
Try to get a Volvo service and parts manual for the engine and drive.

Thank you. I ordered the nipple through volvo and will wait on that and then if it continues will try the o ring. I do have a service manual as it came with the boat when I bought the boat used.

 

[Scott Danforth]

if you bought the sierra one, its the same volvo part, just at a much much much lower price