water not cycling

[imported_roy]

'75 volvo penta. With motor flusher on, and motor running, no water cycles through the engine. Water pump, however, seems to be working properly. What could this be. New to boating. Please help! Worried.

 

[Mahoney]

Re: water not cycling

water wont cycle through the engine until your thermostat opens at ~160 degrees. You SHOULD have water flowing to the thermostat housing and routing out through the manifolds and out exhaust though until you reach that temp.

 

[imported_roy]

Re: water not cycling

temp gauge got pretty high and no water was getting to the water pump. there was no water coming out of the exhaust and it seemed that no water was entering the outdrive as there was no decrease in water hitting the ground. ???

 

[rodbolt]

Re: water not cycling

are you sure no one has converted it to a through hull pickup ?

 

[imported_roy]

Re: water not cycling

if by through hull you mean through the hull of the boat, which would be a separate hole or inlet that leads to the motor, that would be a negative.

 

[Mahoney]

Re: water not cycling

I would make sure the water hose to the thermostat housing is pumping water, I am guessing thats really the only way you would know if the impellor is working properly, then time to take the thermostat out and test it. Depending on when the last time this was run and cooling correctly, you could have a pretty big mess inside that housing and the thermostat might be shot.

 

[imported_roy]

Re: water not cycling

Llast weekend was the first time we took this boat out. We just bought it. The first time we took it out to test it was Friday. It ran great except for a water leak from a copper tube on the side of the engine leaking pretty bad. The temperature gauge was reading a little warm but not quite in the red. I fixed the leak which was seals not seated properly. Saturday, it seemed to run fine in neutral, but when I put it into gear (D or R) it didn't want to run properly. It was as if something was holding the propeller and holding it back. The temperature gauge was reading perfect. Now it seems that no water is getting into anyting.

 

[Mahoney]

Re: water not cycling

Hmm, water leak from copper tube? I am not farmiliar with the drive you have, but is your setup fresh water cooled? Does it have a heat exhanger and coolant? I dont have fresh water cooling, but I cant imagine any kind of copper tube that water would be leaking from on a motor of that vintage unless it was using fresh water cooling.

If that was leaking bad, it might have leaked out all your coolant, which would explain a lot

 

[imported_roy]

Re: water not cycling

no extra cooling system. All water lines come from and lead to the outdrive. It is a Volvo Penta 130 4cyl. with a 270 outdrive. Is there possible an impeller separate from the water pump that may assist in water cycling that may have gone bad?

 

[imported_roy]

Re: water not cycling

There is a rubber flex hose, about 3"diameter, between the outdrive and the hull which leads to the engine. There is a hole in this hose. That would lead to the engine sucking air and not getting water into the galleys. However it doesn't solve my original problem, of a loss of power when put into gear.

 

[Mahoney]

Re: water not cycling

you have 2 problems there for sure, I don't know anything about the volvo penta's, I would wait for someone with some experience on those drives to help you out.

To the best of my knowledge there should be an impellor in the outdrive that should be delivering water through that hose, your engine should not be sucking from there, unless your pump impellor bringing in water s mounted to the engine, but I doubt that in a 1975 settup.

I could be wrong, and probably am though, so wait for some volvo knowledge

 

[Don S]

Re: water not cycling

no water cycles through the engine. Water pump, however, seems to be working properly.

If no water comes out the back of the transom shield or drive, how do you KNOW the water pump is working. Or are you just assuming it is ? ? ? ? ?

temp gauge got pretty high and no water was getting to the water pump. there was no water coming out of the exhaust and it seemed that no water was entering the outdrive as there was no decrease in water hitting the ground

Again, how do you know the water pump is ok?

There is a rubber flex hose, about 3"diameter, between the outdrive and the hull which leads to the engine. There is a hole in this hose.

That sounds like the exhaust bellows. It is the lower of the two bellows and has a drain hole in it. That is not your problem. That bellows could be completely missing and the boat will run fine, the prop might cavitate a bit, but the engine will run fine and not overheat.

You engine is raw water cooled, and like all the other engines, did not have a circulation pump. You have a raw water pump mounted on the front of youre engine, Volvo does not use raw water pumps in their drives. You also have a lot of copper tubes in the cooling system. And water should come out the back of the boat even if the engine is cold.

You could have a hose, tube, cooler, exhaust manifold, or exhaust elbow plugged which would prevent water flow. If the pump was good. You could also be sucking air instead of water. A bad impeller, raw water pump shaft seal or bushing, even a bad hose connection on the drive will cause an air leak on the suction side of the pump. When it sucks air, it won't pull the water from the drive.

 

[imported_roy]

Re: water not cycling

I took the front plate off of the water pump where the impeller is and the rubber impeller seemed to be in good shape. No cracks or tears with plenty of plyability. As the engine turned, the impeller acted as it was supposed to. Thank you Don for the info on the exhaust bellows. I was unsure about that as I am unsure about alot of other things with boat drive trains. But I am wanting to know as much as possible. My next step is to take each hose loose one at a time and blow water through them to see if I can find any stoppage. Thanks again. Any other need to's you or anyone else can give me would be greatly appreciated.

 

[JAL51974]

Re: water not cycling

I had a similar problem overheating on the VP AQ125A engine/270 drive. Check all those connections on the copper piping from the raw water pump through the transom and on the outdrive.On the drive the middle of the three rubber connections is a water hose. the hose leads to a metal water connector, the seal under that connector is notorious for rotting and air leaks result. Air leak=not enough water circulating through the raw water system =overheating.

I rigged up a wet/dry vacuum to the copper piping inlet tube at the rw pump and taped off the water intakes at the outdrive (2). Each connection in the piping was smeared with shaving cream- made the spot that was leaking air easy to find! Now I just have to replace the seals and gaskets on that spot.

Hope this helps.

 

[Don S]

Re: water not cycling

Before you go too much farther with your repairs, get a Volvo OEM service manual for your engine. It will help your understanding of how things work together. They are only about 20 bucks and has ALL the information that Seloc and Clymers condenses into unusable information. The part number for the manual is 7723640 and your local volvo dealer can order one for you.

When you start checking hoses for flow, be sure to start right at the pump. If it's sucking air, it won't pump. And that hose connection on the drive is a known weak point. The end of the connection corrodes off inside the hose. Looks great from the outside, junk on the inside. The newer models were plastic, not the aluminum you have.