Impeller Change Frequency?

Franko Manini

Well-Known Member
Folks,

I have a 2010 Suzuki 140DF, it's got very low hours on it. 184 if memory serves. How often do you replace the impeller and does the rubber age when it sits? Meaning, if the motor sat for years and had very few hours on it, would you replace it anyway?

Thanks for your comments!
 
you might be ok but i think one of the benefits to changing it or at least checking the condition of the impeller every couple of years is so that the bolts dont seize up which can be a pain. If i was you id check the impeller condition and for the extra few bucks after 8 years id change it. Also had an issue with the thermostat on my kicker so will be checking that more often on both my motors.
 
You'll find many differing opinions but,
as long as it's pumping water fine, I think you're ok to leave it.
I had a 1999 Honda that ran fine and had only one impeller change in it's life.
I agree it's good to check it periodically.
 
for the price and the ease of changing it I believe 3 years is the recommendation. it is one of those things that works great until it doesn't and you are out on the water.
 
I was told by the Yamaha mechanic that in the Yamaha case if you run it at the house in a stock tank rather than rabbit ears it should be changed every 5 years of 500 hours. Of course he is the one getting paid to change it.
 
You'll find many differing opinions but,
as long as it's pumping water fine, I think you're ok to leave it.
I had a 1999 Honda that ran fine and had only one impeller change in it's life.
I agree it's good to check it periodically.
What Scott said, exactly x 2...
 
Folks,

I have a 2010 Suzuki 140DF, it's got very low hours on it. 184 if memory serves. How often do you replace the impeller and does the rubber age when it sits? Meaning, if the motor sat for years and had very few hours on it, would you replace it anyway?

Thanks for your comments!
How is the tell tale water when running? The purpose is to move water through and if the water is coming out as normal then I would leave it. 3 years is a common rough estimate to replace and is a small price to pay. I agree with the seized bolt issue AND the need to replace a thermostat. Have seen a few very costly repairs due to a malfunctioning thermostat.
 
for the price and the ease of changing it I believe 3 years is the recommendation. it is one of those things that works great until it doesn't and you are out on the water.

Same here. I was told by my local marine mechanic 3 years is about average life and should be changed if for nothing else but peace of mind
 
I’d change it. After 8 years your bolts need some anti seize and the drive shaft splines need grease.
This is so true. I would go so far as to suggest that with a new motor after the first year to drop the gearbox and cover the splines with a marine grease including a small dab on the top. Remember to only turn the propeller in the direction of normal rotation, if you need to rotate it at all.
As far as the impeller goes, if you run it dry or it sits for a few years, change it, other then that, I change them every 5 years (about 500hrs).
Some of the newer engines cannot easily be run on muffs as they have more then one intake. For these engines, you should use a tank when running on the hard.
 
I’d change it. After 8 years your bolts need some anti seize and the drive shaft splines need grease.
great advise. Suzuki 140/175 have a nasty habit of the splines on the shaft locking without a ton of grease. It is a sawz all situation after that.
beemer
 
The biggest problem with impellors is "set". This is when the impellor loses its ability to push against the outside walls of the pump and become inefficient. The impellor is always under pressure against the pump and the blades get "set" and no longer function as they should.
Greasing the drive splines is a good idea. Parts are not expensive. When in doubt change it out. Careful putting grease on the end of the drive shaft. Grease doesn't compress and too much will result in a preload in the thrust bearing surface and lead to premature engine failure.
 
I have. 2009 DF 140 and change mine every two years regardless. As mentioned in earlier comment, the impeller vanes develop a set in them and at eight years, you are probably due for a change out. I can do mine in about 45 minutes with cleaning and greasing everything before it goes back. I recommend anti seize on bolts and water proof silicone grease on housing o- rings and impeller. You want to make sure to put engine in gear before disassembly to avoid rotating engine coupling to pump drive shaft.

There is also a rubber sleeve where the pump discharge pipe goes into pump housing and it is always a good idea to replace it at same time.
 
I just changed mine this year after 5 years since last being changed. Glad I did as one vane was torn half off and the rest had cracks where the vanes attach to the main body... Would have probably self destructed on my next trip.... (this on a diesel engine water pump)
 
I did the job this morning. I took my time and it was done in 90 minutes. I did as suggested and put marine anti-seize on bolts and grease on all the shafts. Lubed up the impeller with a touch of waterproof grease on each tip.

The old impeller was still pliable, barely, but definitely set in its shape. This is a job that’s not too difficult and I’m glad I tackled it myself.
 
I did the job this morning. I took my time and it was done in 90 minutes. I did as suggested and put marine anti-seize on bolts and grease on all the shafts. Lubed up the impeller with a touch of waterproof grease on each tip.

The old impeller was still pliable, barely, but definitely set in its shape. This is a job that’s not too difficult and I’m glad I tackled it myself.

I've used dish soap to lube the impeller fins as I've heard that some greases don't play well with the rubber on the impellers. Just an alternative to grease on the impeller.
 
You can actually purchase rubber grease.
 
The most important part of this maintenance is just dropping the gearcase and lubing the driveshaft spines that engage the lower powerhead. I've seen shops have to destroy (cut) driveshafts to get the bottom end free. The driveshaft welds itself to the powerhead from corrosion. That can be $1500 in replacing that part before doing anything else. Each year I remove the lower gearcase bolts one at a time and apply marine grade never seize to them and re-tighten. On the 2nd year I drop the leg, change the impeller and apply grease to the splines on the top of the drive shaft. I was told to keep the grease off the very top of the shaft...I guess it can make it hard to get it back together as it gets compressed inside the coupler and has no where to go.
By doing this I can have the gear case off in 15-20 minutes and can change the impeller and have it back together in under an hour.
 
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