volvo aq 170 overheating

[Don S]

Did you check to see if water was coming out of the exhaust while it was running? If not, the first place to check would be the impeller. Pull it out and see if the vanes straighten out in about 15 minudtes or less, if not, but a new one in with some dishwashing liquid on it and try again.<br />There is also a hose connection that may be corroded away that is on the drive just below the ujoint bellows. If it corrodes off, the pump will suck air and not water.

 

[Dunaruna]

Re: volvo aq 170 overheating

Hi Newt, welcome to i-boats. Time for a new raw water impellor and flush, the impellor blades will still deteriorate & 'set' even when not in use. When using a garden hose does water pass freely from the sea water strainer to the outdrive, if so then your oil cooler is all clear.<br /><br />You mentioned heatexchanger, is it fresh water cooled or were you refering to the oil cooler?<br /><br />Aldo

 

[Dunaruna]

Re: volvo aq 170 overheating

Woops! Didn't realise you posted Don.

 

[Don S]

Re: volvo aq 170 overheating

The impeller is only three years old, with less than 20 hours.

Doesn't matter how many hours are on it, if it's been sitting for a long time it's probably taken a set and won't pump.<br />Along with that, loosening the screws on the pump will cause it to not pump. If this was done with it running, you need an impeller. <br />After running for only 15 seconds with no water, they will get hot and take a set and then they can't pump. The look good, they just don't work. Any other air leaks before the pump will also cause it to "Not Pump".

 

[newt5005]

volvo aq 170 overheating

This is a 1973 170 hp Chrysler I-6 in a 18 foot tri hull. It has never been in salt water. I had the seawater pump rebuilt 3 years ago by a professional boat shop.I didn't have trouble the rest of that year or the next year and didn't use the boat at all last year.I stored it outside all year long.It will not cycle water for cooling at all.It heats up in a matter of minutes. The impeller turns, is good and there are no restrictions in either of the hard pipes that connect to the pump or the rubber line that the water comes in, through the transom.I do not know how to check the heat exchanger for the oil for blockages, or even if that would be the next step.

 

[Don S]

Re: volvo aq 170 overheating

After I install the new impeller,is there a way to prime the system so that the new impeller does not get toasted?

Using the dishwashing liquid will protect the impeller till the water gets there.

 

[Dunaruna]

Re: volvo aq 170 overheating

Self priming, just use a liberal amount of rubber safe grease in the housing - don't be afraid to smear it around (water based grease like KY). As don said, it doesn't take long to fry the blades.<br /><br /> Fresh Water Cooled would mean you have a large heatexchanger with a radiator cap and the block is filled with coolant - not lake water. <br /><br />Aldo

 

[newt5005]

Re: volvo aq 170 overheating

no water accompanies the exhaust. A very small amount makes it to the impeller as witnessed by running the motor with the impeller screws loosened. almost no water makes it to the manifold. This is verified by checking the petcocks after running the engine with supplied pressured water. Re this hose connection, would (watermuff)pressured water leak out anywhere that might indicate this? I do have the 'leak out hole'at the bottom of the outdrive plugged during testing. The impeller is only three years old, with less than 20 hours.

 

[newt5005]

Re: volvo aq 170 overheating

the boat is fresh water cooled and yes, that would be the oil cooler

 

[newt5005]

Re: volvo aq 170 overheating

Thanks so very much for your quick responses. After I install the new impeller,is there a way to prime the system so that the new impeller does not get toasted?

 

[Ouan]

Re: volvo aq 170 overheating

Yes I use lots of a lithium based grease in the impeller housing of our Volvo and never have a problem

 

[Don S]

Re: volvo aq 170 overheating

You don't need "Lots" of grease, all you need is a thin layer to lubricate (dishwashing liquid works great) long enough for the water to get to the pump. Usually only a few seconds.<br />A raw water pump is designed to use water as a lubricant, no need for petroleum products at all.

 

[Ouan]

Re: volvo aq 170 overheating

Well, the engine is 36 years old and I like to ensure the impeller does not get eaten up on start up particularly at the begining of the year when it is started out of the water before lift in. I also coat the paper gasket on the housing plate. I have run into problems when I have any lack of a seal as the pump will not draw water. I have also had problems when the skeg intake sucks up weeds and get stuck in the oil cooler and the pump runs dry. They tend to be a little thick around here and hard to avoid sometimes. I have not had any problems using<br />this grease but others may.

 

[rabidfish]

Re: volvo aq 170 overheating

You also need to look at the hose fitting on the drive. They had a history of corroding off.<br />Where the water hose meets the drive unit. Remove the hose & inspect the fitting. any air leak could cause this symptom