Impeller life in outboard motor

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4WD

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Did not find much in search, so here goes:
Looking for real world feedback on impeller change - some say hours - some say based on time saying it has a "memory" - said differently - they will loose restoration force over time.
I am running low hours - flush both ways - and have pump pressure guage ...
 
I've wondered about this myself. I've got an 1975 Johnson 25hp that gets maybe 15-30hrs a year on it and my impeller is 5ish years old. I think I'm going to let it ride for another 5 years.
 
IMHO impeller failures are from a lack of use and temperature changes while stored. We change every 2 years, but when we are out we are 20+ miles away from where we launch. That is a LOOONg expensive tow.
 
Originally Posted By: InhalingBullets
IMHO impeller failures are from a lack of use and temperature changes while stored. We change every 2 years, but when we are out we are 20+ miles away from where we launch. That is a LOOONg expensive tow.


^^ This has been my experience. On a regularly used OB or I/O, they last a long time.
 
Thanks all - I launch at my camp and never get over a couple miles away - there is some boat traffic around - small bay and back lakes (brackish water where my Boat barn/lift is).
So, based on this - feel like I can go 3-5 years - and if I'm not going fishing - a good 10 minutes purring on the fresh water hose will help keep the pump and other stuff in shape ...
 
5-6 years. On mine it will start running hot when idling in the no wake zones. Of course now the water is 90 degrees anyways, so it runs a bit hot just because the water cooling it is hot already. Of course the dealer recommends every two years. For the average moron boater I would agree with the guy.
 
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Change them on a time schedule. For my inboards it was always every 3 years. Once you have one disintegrate and have to get the 10,000 rubber pieces out of the cooling system you will jump at replacing them before that ever happens again.

Don't ask how I know this. Use a little Vaseline in the housing to prevent a dry start.
 
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We just got back from our week long trip to Venice, LA. Our last day was wasted because we started having overheat alarms going off. We had to idle in 29 miles! That sucked! The engine was pushing water and was not really that hot to the touch. After getting home we pulled the lower unit to inspect the impeller and wouldn't you know it was completely intact. A few days later we sent it to a yamaha mechanic and he found that the impeller housing was bad.
 
Sorry to hear that, but glad you made it safe ...
Any idea how long that pump kit had been in the motor ?
 
I change mine every 2 years. The memory is one reason but they get brittle after a while regardless of use.
 
For those new to outboards... life of an impeller is measured in seconds if the engine is started without proper water flow to keep it lubricated.
 
I bought a 1984 Evinrude 8HP last year and it still has the original impeller and it pumps great. I have only had time to put 3 hours on it so may not last
 
Originally Posted By: Sealbilly
I change mine every 2 years. The memory is one reason but they get brittle after a while regardless of use.


Yes, best practice is to give the cord a pull every few months to move the impeller to a new position
 
Originally Posted By: 4WD
Sorry to hear that, but glad you made it safe ...
Any idea how long that pump kit had been in the motor ?

I gather you were referring to me...the impeller itself was 2 years old, the housing was original(2008 Yamaha F250). We had changed the thermostats before we left, so we wondered if one of the new stats was bad, but that wasn't the case.
 
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