Overheating!

LHUDSON

Seaman
Joined
May 31, 2011
Messages
58
I have a volvo 4cylinder AQ125.It does not overheat until I open it up at high throttle.When idling it is fine.I changed the thermostat and inpeller.I flushed the heat exchanger out and made sure all water supplys had good flow.Compression is at 140 to 145 on all cylinders.Only thing I have not changed out is the fresh water pump.I will check it but could it be anything else?
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Overheating!

Check the hose connection where the water hose connects to the drive. They tend to corrode away inside the hose where you can't see. Then the pump sucks air because it's above the waterline when on plane.
 

ajax5240

Petty Officer 2nd Class
Joined
Aug 6, 2011
Messages
134
Re: Overheating!

What Don said, or the bushing in the drive that holds it tight up against the gasket to that elbow. In mine it was pretty much gone. Got new bushings, pressed them in, and runs great now. Just wish I could get back all the money i spent on things that weren't broken chasing this problem... Oh well.. guess that's boat ownership for you.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
17,923
Re: Overheating!

What Don said and if that's not it?? The manifold will probably need replacing.
Not sure of the year??? but he 125 was made in the early 80's and if the manifold is the original it's WAY old and probably loaded with rust, corrosion.
Flushing doesn't always work on these older ones.
The paint looks good but the inside is bad.
 
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