125AQ Overheating Problem

In searching for help on my cooling problem for my '83 Bayliner Capri, I stumbled on a forum from 2005 that explains all the problem I am having with the Volvo AQ125, however I am not mechanically inclined enough to know how to reference the problem parts with Volvo item numbers. I am certain I can do the fix myself, just need some guidance on what parts I need. The original poster explains the "removal of the gooseneck on the outdrive, replace the gasket, hose and clamps and she was good to go" Apparently this part corrodes and begins to suck air, thus inhibiting the cooling system to circulate. Sounds like a winner to me, I have replaced the housing for the impeller and the impeller, she's pumping great... Just need the closed system to stop overflowing.... Please help

Re: 125AQ Overheating Problem

If you are getting plenty of water through the raw water pump then the water pickup is probably not your problem.
We will need some more information on what the exact problem is. I assume that when you say the closed system is overflowing that it is actually over heating and causing the coolant to run out?
Is this confirmed with the temperature gauge?

Does it overheat at idle on muffs or only when under load?

I had an incident with mine where the raw water hose between engine and transom was kinked and restricted the flow. It would idle all day but at higher RPM it had problems. they are using a straight piece of hose to make a 90 so over time it will kink and flatten.
I replaced it with a piece of radiator hose that had the 90 in it and it has worked great since.

Please see the diagram on this link Connecting Components AQ120B, AQ125A - 7742840 - Volvo Penta
Based on your description it is item no. 53 that will corrode.

If you look at this link you will see items 28 and 29. Note that 53 on the previous print and 28 on this print are the same part.
Intermediate Housing: Drive 270 - 7742840 - Volvo Penta

I would recommend to replace the hose, hose clamps, hose connection and gasket.

Re: 125AQ Overheating Problem

Volvo Penta 854031-2, GLM 23011 - Sierra 18-2777 - iboats

save yourself 20 bucks and buy this one, comes with the gasket.

I would argue that to replace that seal and elbow, you may want to remove the upper gear box as well. It makes is much easier to install, and its easy to install that gasket wrong. Ask me how I know...

Re: 125AQ Overheating Problem

Alan Lloys said:

If you are getting plenty of water through the raw water pump then the water pickup is probably not your problem.
We will need some more information on what the exact problem is. I assume that when you say the closed system is overflowing that it is actually over heating and causing the coolant to run out?
Is this confirmed with the temperature gauge?

Does it overheat at idle on muffs or only when under load?

I had an incident with mine where the raw water hose between engine and transom was kinked and restricted the flow. It would idle all day but at higher RPM it had problems. they are using a straight piece of hose to make a 90 so over time it will kink and flatten.
I replaced it with a piece of radiator hose that had the 90 in it and it has worked great since.

Please see the diagram on this link Connecting Components AQ120B, AQ125A - 7742840 - Volvo Penta
Based on your description it is item no. 53 that will corrode.

If you look at this link you will see items 28 and 29. Note that 53 on the previous print and 28 on this print are the same part.
Intermediate Housing: Drive 270 - 7742840 - Volvo Penta

I would recommend to replace the hose, hose clamps, hose connection and gasket.

Click to expand...

Indeed, the radiator is overflowing and the temp gauge reads 240+. Only when I am at 4000 Rpm for a while will it spike. Almost immediately when I come back to idle, the temp returns to 180. This is very helpful information, thank you.