Water flow to raw water pump inlet.

[99xjjoe]

1996 sx cobra, 5.0fl volvo, Impeller blew so boat ran around 200 degrees. Installed new impeller and find old impeller chucks. Now i want to run the motor but want to verify that water is flowing to the raw water pump. Would hooking muffs up with the inlet hose to the raw water pump off show flow? Thanks Joe

 

[PS94]

Re: Water flow to raw water pump inlet.

nope, you'll have to try it on the lake or with a large container of water around the leg. The water pressure from the hose will push the water in regardless of what the lift pump is doing....

 

[99xjjoe]

Re: Water flow to raw water pump inlet.

ok so with the muffs on and hose on high i should have water coming from the inlet hose to the pump? Because i dont.

 

[jerome radtke]

Re: Water flow to raw water pump inlet.

Yeah, a hose would be pushing water, whether the impeller was working or not. So you need the sterndrive unit in a tub, or lake, in order to see if it pumps on it's own.

Sounds like you have not done it correctly, or some other obstruction exists.

 

[tkrfxr]

Re: Water flow to raw water pump inlet.

ok so with the muffs on and hose on high i should have water coming from the inlet hose to the pump? Because i dont.

You just found the problem....

 

[Don S]

Re: Water flow to raw water pump inlet.

ok so with the muffs on and hose on high i should have water coming from the inlet hose to the pump? Because i dont.

Probably not. The hose and muffs don't push hard enough to push the water uphill through the drive and transom shield. Too much leakage around the muffs.

 

[tkrfxr]

Re: Water flow to raw water pump inlet.

:facepalm:duplicate post

 

[tkrfxr]

Re: Water flow to raw water pump inlet.

You can try flushing backward from the inlet hose out to the outdrive toflush out any restriction to the flow....this is what would happen if you had a flush system in your engine... you would see the water come out of the inlet passages on the outdrive.

Either way, you should look at the condition of the impeller once you find the problem, to make sure it did not get damaged during the time you worked out the problems...if you turned on the engine....

If the impeller was old and simply failed, then put the boat in the water and see what it does.

 

[99xjjoe]

Re: Water flow to raw water pump inlet.

I put the outdrive in bin of water with muffs and hose(sounds strange but it worked), water flowed within afew seconds through the motor, ran for 20 mins temps sat at 160. I dont understand how the flow to the raw water pump starts. Im a mechanic and this system makes no sense how flow is created. So when the boat is in the water and i start the motor, the impeller will always spin dry for afew seconds until the water reaches it? Thanks for the help Joe

 

[Don S]

Re: Water flow to raw water pump inlet.

If you have wimpy water flow from either low pressure on your hose, or even just long hoses (100 ft or more) it's likely you won't get the raw water pump to pick up..

Your raw water pump creates suction, and pulls water up from the outdrive. If there is an air leak in any of the connections, you will have problems.

When an impeller fails and you overheat, raw dry high temp exhaust goes through the outdrive. There are rubber grommets and seals for the water tube. if they burn, you got an air leak. Might want to drop the lower and check things. You may have water now, but I wouldn't count on it lasting.

Might want to look at this overheat files. http://www.4shared.com/file/50572185/e88f1d89/Volvo_Penta_Overheat_Diagnosis.html