# Waited a bit too long



## southerncannuck (Jun 27, 2016)

In the mindset of you learn something everyday today’s lesson is that 4 years is too long to run the original water pump and thermostat.

Nothing bad happened but the impeller and t-stat looked very bad. I’m a bit surprised by the thermostat because I use salt away after every trip.
Lesson learned is change them yearly. It’s easy to do.


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## JC Designs (Apr 5, 2020)

southerncannuck said:


> In the mindset of you learn something everyday today’s lesson is that 4 years is too long to run the original water pump and thermostat.
> 
> Nothing bad happened but the impeller and t-stat looked very bad. I’m a bit surprised by the thermostat because I use salt away after every trip.
> Lesson learned is change them yearly. It’s easy to do.


Exactly! Ya know, I always recommend annual replacement of water pumps “been a tech for over twenty years” and the key board cowboys tend to second guess me a lot! Glad nothing bad happened and you didn’t get stranded or hurt the motor!


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## not2shabby (Sep 14, 2016)

Yes. 4 years is too long. They're a whole lot cheaper than the alternative! Glad you didn't have any major issues. I agree with you on the tstats looking pretty bad even if you use saltaway. Gotta wonder what the water jacket looks like, too.


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## southerncannuck (Jun 27, 2016)

not2shabby said:


> Yes. 4 years is too long. They're a whole lot cheaper than the alternative! Glad you didn't have any major issues. I agree with you on the tstats looking pretty bad even if you use saltaway. Gotta wonder what the water jacket looks like, too.


 The water jackets, at least what I could see with a flashlight were free of corrosion but one side had a greasy/muddy Surface coating.
I hate to spend the money but I’ll order a mercury service manual. I’ll at least have access to the proper torque specs for any further maintenance.


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## mwolaver (Feb 6, 2014)

Can you give a bit more info? Do you know how many hours you put on that impeller? When you say 'bad', what did it look like? Arms just took a lot of set? or were they breaking down? Was the engine still peeing pretty hard? 

Yamaha says 300 hours for the lower unit...That's quite a while for some folks. I used to do the pump every year...and never saw an impeller that was coming apart or breaking down. Several engine specialists I know recommend replacing the upper lower unit seals (under the pump) each time the pump is maintained.


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## SomaliPirate (Feb 5, 2016)

It takes about as long as changing the oil in your car (unless you have a 7.3 Ford, which holds like 50 gallons of oil). Do it yearly.


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## JC Designs (Apr 5, 2020)

southerncannuck said:


> The water jackets, at least what I could see with a flashlight were free of corrosion but one side had a greasy/muddy Surface coating.
> I hate to spend the money but I’ll order a mercury service manual. I’ll at least have access to the proper torque specs for any further maintenance.


There tends to be a lot of dissimilar metals in a t stat. That’s most likely the reason it looked so bad. The salt away is probably doing it’s job but can’t do anything about dissimilar metals.


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## southerncannuck (Jun 27, 2016)

The engine has about 190 hours on it. Mercury recommends replacing the pump at 300 hours or 3 years. Here’s the brain dead senior moment part. I thought it was 3 years old. I happened to look at the paperwork from the purchase and saw that it was 4 years old.


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## SomaliPirate (Feb 5, 2016)

Looked like it was in really good shape to me though.


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## southerncannuck (Jun 27, 2016)

SomaliPirate said:


> Looked like it was in really good shape to me though.


Shouldn’t it be pliable and return to its original shape. I’ve never done one before. I really don’t know.


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## jmrodandgun (Sep 20, 2013)

I don't hate that impeller.


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## State fish rob (Jan 25, 2017)

^^^ I agree. Wouldn’t sweat it. Sierra brand impellers are supposed made w/ a better rubber compound than stock. Last one I swapped had no corners , no problem gremlins showed up at high rpm. Peed great all the while. Who knew. Much larger outboard tho.


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## JC Designs (Apr 5, 2020)

4 years, the rubber is setting and will not pump the volume or pressure it’s supposed to folks! Do as you wish, this outboard tech changes his annually! Save pennies today, spend thousands tomorrow. Your choice, your money. Carry on!


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## SomaliPirate (Feb 5, 2016)

southerncannuck said:


> Shouldn’t it be pliable and return to its original shape. I’ve never done one before. I really don’t know.


I'm no expert, but that's how mine look when they come out and I replace every year.


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## mwolaver (Feb 6, 2014)

I understand the engineering, JC D. Agree with the pump capacity decline. I also believe that our engines probably don't need all of the actual pump capacity to stay cool. Thermostats restrict flow more that we think. 

I will stick with "annually is overkill" and go with the 300 hrs or 3 years. (I also go 10k miles on synthetic in my truck, so take this with some salt.)

JC D: do you recommend doing the upper lower unit seals with the pump? Or at least do a pressure check?


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## JC Designs (Apr 5, 2020)

mwolaver said:


> I understand the engineering, JC D. Agree with the pump capacity decline. I also believe that our engines probably don't need all of the actual pump capacity to stay cool. Thermostats restrict flow more that we think.
> 
> I will stick with "annually is overkill" and go with the 300 hrs or 3 years. (I also go 10k miles on synthetic in my truck, so take this with some salt.)
> 
> JC D: do you recommend doing the upper lower unit seals with the pump? Or at least do a pressure check?


Impeller annually needed or not, full kit biannually needed or not. Cheap insurance.


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## SomaliPirate (Feb 5, 2016)

I do it annually because that's 45 minutes where I'm outside of my house and away from my screaming kids. Maybe I should start replacing weekly.


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## devrep (Feb 22, 2009)

I think the materials have come a long way since the annual change days. 2 or 3 years is fine for me. I will say if you use the boat a ton of hours like a guide your mileage may vary. then again sometimes rubber compounds stay in better shape when they are used frequently then sitting idle in the heat.


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## JC Designs (Apr 5, 2020)

My last post on this one, I hope. I will leave ya’ll with this... If you are willing to spend $2-4k to save an hr’s work and a $100 tops every year then by all means please do so! Guys, I don’t sell parts and I no longer do service work except for a small handful of clients so take this to heart... I have nothing to gain or lose in offering my professional advise here. Do as you wish, this wrench will continue to change his own impellers annually.


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## Salty Dawg (Mar 10, 2020)

The slot in the impeller for the Woodruf key looked rounded when I enlarged your photo by clickng on it.


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