Just out of curiosity about impeller

[rpatton]

Hi guys what are your thoughts about a stringer water pump impeller being bad but being disguised by someone using the muffs on city water. In other words will a bad impeller show up while using muffs, any thoughts?

 

[southkogs]

Re: Just out of curiosity about impeller

I think the only way to verify it for sure is to look at it. When was the impeller last changed?

I'm no expert, but my best guess to answer your question is "possibly, but I doubt it."

 

[rpatton]

Re: Just out of curiosity about impeller

I think the only way to verify it for sure is to look at it. When was the impeller last changed?

I'm no expert, but my best guess to answer your question is "possibly, but I doubt it."

Well to answer your question is that it was working fine but then I blew a head gasket and I replace it with no issues. Then when I started it on muffs I was more worried about the motor and valve adjustment , then prolly about 30 seconds or so I noticed that it was not drawing up the water to the motor, to much leakage around the muffs. So I put the hose on the water connection at the top of the drive at the caps and had plenty of water at the pee hole and motor, the oly problem is I do not know if I screwed up the impeller or not. Which take me to my question. I know people wll just say to replace it ut it is a saltwater drive and every one tell me that replacing the impeller on a stringer is a lot of work and expensive even if you can get it apart.

 

[BoatDrinksQ5]

Re: Just out of curiosity about impeller

Yes the cold water being injected into the lower unit makes for plenty of cooling at idle even if the implellar is getting stiff/weak.

To uncover possible issues - idle at the dock and watch the temperature closely - should come up very very slow and stop at the thermostat temperature (same as when on muffs). Although in my experience that can take a good 10minutes or more at fast idle.

Typically if a impeller is starting to get lame it will overheat at idle, but be fine when at speed (water jetting into ports because moving).

But anyhow....when it doubt....change. Way better then possible damage caused by overheating (blown gaskets, warped things, etc) or a shredded impeller going into your engines cooling system (have to backflush...etc).

 

[rpatton]

Re: Just out of curiosity about impeller

Yes the cold water being injected into the lower unit makes for plenty of cooling at idle even if the implellar is getting stiff/weak.

To uncover possible issues - idle at the dock and watch the temperature closely - should come up very very slow and stop at the thermostat temperature (same as when on muffs). Although in my experience that can take a good 10minutes or more at fast idle.

Typically if a impeller is starting to get lame it will overheat at idle, but be fine when at speed (water jetting into ports because moving).

But anyhow....when it doubt....change. Way better then possible damage caused by overheating (blown gaskets, warped things, etc) or a shredded impeller going into your engines cooling system (have to backflush...etc).

Thanks for the repleys , has anyone had any experience with changing an impeller on a 1985 stringer 400 drive, are they as bad and complicated as my mechanic says or is he just blowing smoke up my shorts.

 

[Howard Sterndrive]

Re: Just out of curiosity about impeller

nothing difficult, but more involved than any other type of outdrive.
Get the factory manual and when they say to take the battery right out of the boat before removing shift cables- they mean it. .

 

[rpatton]

Re: Just out of curiosity about impeller

Did you have any issues with shafts being corred or anything like that.
How far into the upper is it

 

[southkogs]

Re: Just out of curiosity about impeller

It's at the base of the upper gear case. Once you remove the out-drive and take off the exhaust housing, the upper lifts right off the lower.

FWIW - I would probably do as BoatDrinks suggested and plop it in the water and idle it at the dock. Watch the temp, if it evens out where it's supposed to be and holds you may be just fine.