Engine Impellers

Hamdog

Hey Guys,

 

How often do you change out your engine impellers? I was told they last longer if the boat stays in the water. Mine have 4 seasons on them. Should I change them this spring?

 

2005 342.

 

Thanks,

 

Hamdog

Black_Diamond

I change mine every 3 years, depending on hours of course, but I average about 40/year or so.  Over 3 years is just a losing gamble IMO.

hanzelvh

how many hours do you advice?

jmoen438

I go every other year to be safe. The boat is an 05, so I change them on the odd years.

BoatAway

agree that 4 years is pushing it. a boat staying in/out of the water shouldn't make too much difference on how long it lasts. the water pump stays full of water whether the boat is in or out... unless it dries out from long periods of not being used.

2-3 years depending on hours. less if you've gotten into sand/dirty stuff with the drive... which can tear up the rubber...

Dream_Inn

No matter the hours or in the water, every two years as Al stated is what is do.  I've removed all the hoses on friend's boats because they went too long and then the pieces get lodged further down the line.  It's the age that get to them.  I believe less hours is actually worse because they sit in one place.  Those of us in the north definitely are harder on them because of the time they sit in the winter.  I replace mine every other spring and it is amazing the shape they "set" after winter.

TikiHut2

A lesson I learned on our Merc brass seawater pump that was pretty well documented in another thread, was that if your engine has a brass seawater pump($430e for parts alone) that has signs of grooves/wear in the faceplate and a new impeller won't seat/prime well, there is a machinist in California who sells a SS faceplate for a like-new and tougher seating surface($45 Ebay I think).

The other, far more important tip is to pull your old impeller and take it with you to the parts counter to MAKE SURE it's exactly identical in height/diameter (see pic). As Al pointed out in my other thread, there was a recall on some of the Mercruiser OEM impellers and you might get one that'll be just a smidge(3/32") too short and won't prime(even the ones that were re-stocked as within spec). Of course I got one and took my pump out 3 times troubleshooting the mystery. To make it right Mercury sent me a brand new $430 pump assy if I'd simply return the defective impeller for my trouble. I considered it great customer service but I'd have rather just gotten the right part the first time so check CAREFULLY. The upside is that I can now change an impeller in minutes.

Good luck, Mike

Black_Diamond

I'm amazed they made these wrong. It's like a new die mold was used and never qualified with a ppap.

TikiHut2

Maybe the compound was upgraded and exhibited shrinkage over time that they didn't anticipate......or is that what you said?

Merc thought they had it figured out with a bulletin to all suppliers to check their stock and place a green dot on those that measured to spec or return their stock for replacement. Mine was OEM, sealed AND had a green dot but still clearly came up short. They were all over it when I called Merc directly who assigned a top guy to my case once they saw the above pic that was taken at the Merc dealer parts counter.

Thanks to Al for the heads up that solved my mystery and to Merc for rectifying my problem while also aggressively perusing a larger fix.

Black_Diamond

Usually...when you replace a die, change material or even batches of material you run parts and verify the parts are correct. The ppap process is quite extensive and designed to avoid these problems.