Outboard engine Impeller Replacement

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David Ray

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Polling the WW group on replacing impellers. 300hrs seems to be the general consensus. Our boat is strictly fresh water.
 
Supposedly the new material that Mercury now uses is good for three years. I had a Volvo Penta outdrive that ate the things yearly. On my new 90 Mercury my dealer said three years, Guess it depends how often you use the boat and where it is parked. The desert heat in Tucson seemed to shorten the impeller's life. I changed the impeller on my 20HP Suzuki every two years as it was very easy to do. YMMV
 
For non-commercial boaters, age of the impeller is probably the best way to determine replacement cycles. Most of the hour-based specs are for regular, or daily, use cases - think work boats at Lake Powell, or the rental fleet. They probably hit 300 hours in a season.

In the case of a personal fishing boat, if you're doing 100 hours each year, three years would match the consensus you mentioned. I'm lucky to get 100 hours in three years (mostly small lakes), so I'll change at the 3-year mark regardless. Another factor to think about is the quality of the water you most frequently operate in. Whatever water you're in gets pulled up through the impeller. If it's laden with debris from runoff, etc., the impeller takes the first hit.
 
BartsPlace said:
For non-commercial boaters, age of the impeller is probably the best way to determine replacement cycles. Most of the hour-based specs are for regular, or daily, use cases - think work boats at Lake Powell, or the rental fleet. They probably hit 300 hours in a season.

In the case of a personal fishing boat, if you're doing 100 hours each year, three years would match the consensus you mentioned. I'm lucky to get 100 hours in three years (mostly small lakes), so I'll change at the 3-year mark regardless. Another factor to think about is the quality of the water you most frequently operate in. Whatever water you're in gets pulled up through the impeller. If it's laden with debris from runoff, etc., the impeller takes the first hit.
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All my boat time is Powell. I’m at 275 hrs since replaced (2016). Garaged boat.
 
Love everyone's input...my 2 cents: If you are thinking about it...change it...then you get a new impeller AND piece of mind.

Rivergoer rightly mentioned 'memory'....so true....because they are off center, if the motor sits, some blades are bent and have the memory.

last thought.....I ALWAYS have a spare aboard.....cheap insurance.... ;)
 
Buy the impellers, keep them onboard, watch your gauges, take notes. When the needle starts to climb at idle and goes down at full throttle it's time to change them. Basically I don't fix things that aren't broken. If you plow through a lot of sand and pebbles you can eat one up in a day, I pull my pontoon off a lot if sandy beaches in reverse, to me the hours are meaningless, Is it working is my question?
 
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Squirrel said:
The other thing that eats impellers is “Dry Starting”, meaning checking to see if the engine, runs out of the water. Sq
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Right, also over rerving on rabbit ears and your garden hose. You shouldn't rev it beyond 2,000 without it being in the lake or in a test tank.

Mistreat you impeller and you may be changing then every 20 hours
 
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On my inboards I have mostly followed the 3 year rule. I’m beyond that in my current boat but also have one on board and the tools to change it. I’ve never pulled an impeller personally that looked anything other than new. I think if you treat them right and avoid the dry starts they will last a long time.

I can easily change the impeller on the inboard on the water so a mid vacation swap is less problematic than on an outboard where you need to pull the lower unit.

All that said, I bought a NOS Honda 8 HP kicker when I got my first “real” fishing boat in about 2012. The Honda is an early 2000’s model. It still has very few hours on it. And is on the original impeller. It’s on my list to change in the off season. Wonder how it will look.
 
Just change my impeller, it had only been 7 years....haha. It was the first time out of the water in 6 years. Impellor certainly had every finger bent, but wasn't cracked at all. No idea how many hours, probably under 300 though
 
Ryan said:
On my inboards I have mostly followed the 3 year rule. I’m beyond that in my current boat but also have one on board and the tools to change it. I’ve never pulled an impeller personally that looked anything other than new. I think if you treat them right and avoid the dry starts they will last a long time.

I can easily change the impeller on the inboard on the water so a mid vacation swap is less problematic than on an outboard where you need to pull the lower unit.

All that said, I bought a NOS Honda 8 HP kicker when I got my first “real” fishing boat in about 2012. The Honda is an early 2000’s model. It still has very few hours on it. And is on the original impeller. It’s on my list to change in the off season. Wonder how it will look.
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It is a Honda, it will look and act like new.
I’m betting you don’t see a difference in the stream even after installing a new one.
Even though I still respect Merc’s, Honda/Suzuki/Yamaha is kicking our butt even in the impeller game.
Sad.
 
Ryan said:
On my inboards I have mostly followed the 3 year rule. I’m beyond that in my current boat but also have one on board and the tools to change it. I’ve never pulled an impeller personally that looked anything other than new. I think if you treat them right and avoid the dry starts they will last a long time.

I can easily change the impeller on the inboard on the water so a mid vacation swap is less problematic than on an outboard where you need to pull the lower unit.

All that said, I bought a NOS Honda 8 HP kicker when I got my first “real” fishing boat in about 2012. The Honda is an early 2000’s model. It still has very few hours on it. And is on the original impeller. It’s on my list to change in the off season. Wonder how it will look.
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Having dealt with half dozen Honda outboards [7.5, 8,9.9,and 15's[ I'd change them before they start "shedding" rubby chubbies". They seem to have a tendency to push particles of rubber into very difficult places to remove causing overheating issues later on. Just my experience.
 
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