Thread: Impeller change
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Old 03-21-2017, 12:13 PM   #10
LarryM's Avatar
City: League City, TX
Country: USA
Vessel Name: Pelago
Vessel Model: Wellcraft 3300 Coastal
Join Date: Aug 2011
Posts: 936
Originally Posted by cardude01 View Post
Have a 4jh Yanmar.

I replaced the impeller after my trip from Florida to Texas, but have only put about 100 hours on it since here in over a year. Manual says every 250 hours or every year, which ever comes first.

Does everyone replace the impeller every year?
On my Yanmar 4JH3E in Boomarang, I changed it every year, just to be on the safe side. In talking to those in the business though, I am led to believe that impeller life is much more a function of the water, specifically mud and silt, in which the boat is operated. Along the Gulf Coast, Galveston Bay, the ICW etc. with its typically muddy water, the silt content is high and the impellers can wear very quickly, as well as the pump covers, wear plates etc. in the pumps themselves.

The Yanmar JH3 Series Operation Manual states "Note: The impeller must be replaced periodically (every 1000 hrs.)."

The Yanmar 4JH3E Engine Service Handbook states that the Seawater Pump Durability, Impeller Flow Drop of 10% is 1500 hours minimum.

These numbers are way beyond my comfort level. I like seasonal much better.
M/V Pelago
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