Changing the 2-stroke outboard water pump rotor

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Rich

Anybody have any guidance on how and the difficulty of changing the paddle wheel for the water cooling pump? Mine is 10 years old and probably at the end of its useful life. Would prefer to spend an hour changing it than having it disintegrate at an inopportune time. I have a 9.9 Tohatsu (Nissan) outboard. Many thanks. Rich
 
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Phil

no

You would have to drop the lower unit to get to the impeler. If your piss tube is showing a good flow I forget it. If you need to drop the lower unit for a given reason, I'd do it then but just dropping it for an impeler replacement, probably not. If it ain't broke don't fix it. 2 stroke outboard impelers hold up much longer the raw water inboard impelers.
 
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Capt J

Yes

If you read your owners manual, this is a recommended preventitive maintainence item. I agree that this is not going to fail as fast as a raw water pump impeller but they do fail. The time required to change it is less than a half hour and the cost is minimal. The "if it ain't broke don't fix it" is not correct with all items. Just because you have oil in the engine would you not change it routinely? This is a normal wear and tear item like oil, belts, hoses, etc. Why for a half an hour and a few bucks would you chance getting stuck out without a means to get back in. All that is necessary is to drop the lower units and remove a few screws from the impeller housing, slide the impeller off the drive shaft and replace it with a new one. If you wait until it goes bad you will most likely have to replace the housing too and that gets to be quite a bit more costly. Be sure that you spin the impeller back in the housing the way the shaft turns. That will be appearent when you take the old one out. If you do not the blades will be in the wrong direction to pump water and will most probably break off causing you to have to replace it again. Good luck.
 
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PHIL

Fun with motors

I must be lucky. 30 years with outboards 5-150hp and I don't think I ever had to have just an impeler changed. However, if I was ever had the lower unit dropped for seal replacement (oil in the water) or any other reason, I would have the impeler changed. If you are going to do it make sure the lower unit goes back on properly with new gaskets properly seated to ensure no water intrusion into the lower unit.
 
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Warren M.

OB Impellers

Like a lot of things with boats, some tasks start out easy and end that way. Others start out easy and become a nightmare.... Im amazed that your impeller seems to have lasted so long. They are a normal replacement item. Sometimes they warn you of a problem, other times they don't. If you do this job yourself, get repair manual first. The hardest part may be getting the lower unit off. If the motor is 10 yrs old, the bolts holding the lower unit may be rusted or frozen in place. You may need to apply heat (carefully!) to loosen them. Make a mental note or draw a diagram of how the water flow tube and shift linkage connect. If you run into a problem early, take the motor to a professional. The cost of this job is in the $60-$100 range and may be well worth it.
 
Jun 2, 2004
3,648
Hunter 23.5 Fort Walton Yacht Club, Florida
Not A Tough Job

If your a handy guy and beleive that only girls and wusses take their cars somwhere to get the oil changed it is easy. If you have doubts get the manual and have a buddy who has done it standing by. If you have to pay to get it done make sure they let you watch so you can do it yourself next time.
 
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