86 volvo penta aq125a

[sqhurt]

This boat is my uncles and I'm trying to help him get it going.

Last year it overheated on him.So he checked the raw water impellar and said it was shot, fins were pretty much gone on it. After putting new one on it continued to overheat. Since then he hasn't messed with it. I've done some reading on this motor and seen about using muratic acid for cleaning the heat exchanger out. But like to know little more how to before attempting that. Also how should I go about back flushing the raw water? I'm thinking if the impellar was chewed up as bad as he says it was then the chunks of impellar could be clogged in there still causing it to over heat. Appreciate any help, Thanks

 

[captmello]

Re: 86 volvo penta aq125a

your on the right track. Look in the strainer for more impeller parts. If they are clogging the exhaust manifold, you may be out of luck.

It may also have more issues. follow the entire water intake from the outdrive. the intake hose elbow can corrode causing overheating.

 

[sqhurt]

Re: 86 volvo penta aq125a

your on the right track. Look in the strainer for more impeller parts. If they are clogging the exhaust manifold, you may be out of luck.

It may also have more issues. follow the entire water intake from the outdrive. the intake hose elbow can corrode causing overheating.

what should I unhook to back flush the system? Thanks

 

[Nhpatriot]

Re: 86 volvo penta aq125a

If you disconnect the heat exchanger exit pipe and gently put a hose in that end with the raw water pump exit pipe off (can't force water thru the pump) you could try back flushing that way. Remove the strainer in the exchanger first.
The exhaust manifold isn't this easy.

 

[sqhurt]

Re: 86 volvo penta aq125a

If you disconnect the heat exchanger exit pipe and gently put a hose in that end with the raw water pump exit pipe off (can't force water thru the pump) you could try back flushing that way. Remove the strainer in the exchanger first.
The exhaust manifold isn't this easy.

Much appreciated Nhpatriot! If you dont mind could you explain on how to do the manifold as well or point me to where could read about? Once again Thanks

 

[Nhpatriot]

Re: 86 volvo penta aq125a

If your trying to flush impeller parts they really shouldn't have gotten past the strainer. Even the heat exchanger is after the strainer.
If the exhaust manifold is an issue you have to remove it.
You should verify good flow to the heat exchanger first. Remove the exchanger fill cover while running in water and see if you have good flow, it should over flow so be ready but not to the extreme, most should go down thru the strainer and heat exchanger when at idle.

 

[PiratePast40]

Re: 86 volvo penta aq125a

It may also have more issues. follow the entire water intake from the outdrive. the intake hose elbow can corrode causing overheating.

^^^^^^^ If the strainer is cleaned out, and the impeller is in good shape, this is the most common source of overheating for engines with these drives. That fitting is just below the driveshaft bellows and corrosion isn't allways obvious until you disconnect the hose.

 

[Nhpatriot]

Re: 86 volvo penta aq125a

Just re reading this thread, I know the elbow you are referring to, It can be removed while on the boat and after market models are available. Mine deteriorated at the hose clamp but I guess it could clog.
Sqhurt, are you still dealing with this issue?

 

[sqhurt]

Re: 86 volvo penta aq125a

Just re reading this thread, I know the elbow you are referring to, It can be removed while on the boat and after market models are available. Mine deteriorated at the hose clamp but I guess it could clog.
Sqhurt, are you still dealing with this issue?

At this time my uncle is waiting for parts to get here. The water neck was falling apart, so got new one and some o-rings to replace.

 

[sqhurt]

Re: 86 volvo penta aq125a

Well he got the parts and we put on the new water neck and gasket. Checked strainer and impeller. The strainer is like melted kinda where it doesn't fit in the grooves on the side of housing. So pieces was able to get threw to heat exchanger. Impeller was replaced beggining of year so was still good.

So we toke off the heat exchanger and back flushed that and got some pieces out of there. Went to take cover of the exchanger off, and all but one bolt came out. We used heat and everything and still couldn't get it out! So once we get this last bolt out, going to try and clean out heat exchanger with and acid bath. He has access to hydroclic acid at work, would that be ok to dip the heat exchanger in?

With the exhaust manifold, he replaced it at end of season last year cause of a crack in the old one. So hoping the heat exchanger cleaning does it for him this time. Thanks for all the advice and help its been greatly appreciated and helpful

 

[sqhurt]

Re: 86 volvo penta aq125a

Could anyone help me figure out which o rings are on the back of the housing right at where heat exchanger tubes exits? I can't seem to figure out which part numbers these are to replace. And the little o ring/ seal for the plastic housing to the copper tube going to the exhaust manifold? I been on the diagram but can't seem to figure out which is which. Thanks

 

[sqhurt]

Re: 86 volvo penta aq125a

Also This Motor Is A Aq131 series motor, Atleast from the diagrams Iv'e seen for that motor or on point. With having the plastic strainer housing on the one side instead of the plastic and aluminun housing the 125 series has