First and foremost, I want to say I'm glad you're OK and that you were able to obtain help out there on the water.
What was your procedure for seeking help?
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This impeller failure story is disturbing -- and confusing for me.
One post indicated a failure at 120 hrs and another at 50 hrs !!!!!!
This tells me that even if you replace a working impeller with a new one each year there's no real assurance this will prevent a sudden impeller failure.
Can the posters who reported failures describe the impeller failure fault(s) such as vane(s) missing, vanes mangled, bad cracks seen at the root of the vane(s), etc.
Of course these two reported failures are in the face of several hundred R25s not having this problem.
For example, I have just under 250 hrs on our 2010 R-25's Yanmar 4BY2-150 engine and about a month ago had the 250 hr engine service done. At my request I had the technician pull and inspect the impeller. There were no hairline cracks nor missing vanes nor mangled vanes nor out-of-shape vanes to be seen. The technician said there was no earthly reason to replace it even though I was holding a brand new one in my hand.Now after reading this thread who's to say the new one wouldn't fail in 50 hrs or 120 hrs ? I accepted the technician's advice and will keep the new impeller in my spares kit.
I do accept the advice of having the impeller inspected/examined in spring time or before one begins their cruising time.
I suspect with the engine not running and the impeller being located high up on the engine that the impeller does not sit in water. This then means it's high-and-dry for periods of time. My R-25 tends to sit in its covered slip without use for maybe 4-6 months during winter time in the water. Our boat is a little over 3 yrs old so it's been through this cycle 3 times now... and the impeller remains in very good shape. I will add, that during these 4-6 months I will go to the boat to check things and will always run the engine for around 30 mins and take it out of the marina for a quick spin for 20 mins or so, running the engine up to around 3800 rpm for short periods of time. I can do this easily as I live but 5 mins from my marina. If you have your boat on a trailer or held in dry dock this may not be something you can do easily.
When I watched the technician pull the impeller I did not see it as being a monumental task. He removed the vertical portion of the cabin step and exposed the access to the impeller pulley. He then slipped a flat head screwdriver under the impeller's pulley belt and carefully slipped it off. He then aligned the impeller pulley to access the bolts holding the impeller housing. He then removed the bolts and carefully extracted the impeller and inspected it. He then reinstalled things in reverse order. I did not time him but would estimate the time from removing the cabin step's vertical panel to reinstalling this same panel to be no longer than 30 mins. Of course you do need the proper tools... screwdriver, correct socket(s)/socket-ratchet, flashlight(torch) and the ability to lay flat down on your belly. Doing this with the boat heaving and rolling about would be a real challenge of course.
I wonder what the shelf life is for a spare impeller contained in its sealed plastic container ??????
How can we all get a better understanding of this premature impeller failure ?
1) I suspect Ranger Tugs hear most impeller failure stories and I personally would like to know what the failure statistics are that might shed some light on recommended best practices should be adopted to reduce impeller failure risk.
2) If others have replaced their impeller maybe they could describe their repair process and under what circumstances was the repair made.
3) Maybe a impeller failure and/or 'best practice' and/or recommended periodic maintenance survey could be conducted here on this forum.
