Impeller life on Cat 3208s

[Hawkeye]

There was a recent post and very interesting thread about impeller life, storage, after market filtration to keep broken bits out the cooling system, etc. One post reported that an owner of Cat 3208s routinely went 2,500 hours before replacement, very surprising to me! I routinely replace impellers every three years or about 300 hours. Is this boast just misinformation from a sample of one or am I a chump who follows "recommendations" from self-interested parties. How many hours between replacement for you other 3208 owners?

 

[psneeld]

3 yeard and probably 500 to 600 hours was what I got out of mine. It was NJ so the boat was on land for 4 to 5 months and the pumps off the boat with impellers out to "relax".

Do I believe 2500 hours? Sure especially boats run 1000 hours per year or so in clean ocean water. Back waters and silt can shorten their life quite a bit.

But at 200 hrs per year, I felt better after 2 pr 3 years just for Hassel insurance.

 

[jungpeter]

Hi Hawkeye,

I ditto psneeld's recommendation. 500-600 hours/3 years is about right for us yachties with 3208's in recreational service. Strikes a good balance between paranoia and neglect.

Regards,

Pete

 

[Alaskan Sea-Duction]

Last summer, 2021, I put 353 hours on my Alaska cruise. As part of my preventive maintenance, I change my impellers every year. Cheap insurance and when you are many miles from dirt it pays. These impellers cost are relatively low cost. I also keep the best old impellers as spare parts, just in case.

 

[O C Diver]

I posted the 2,500 hour response. The person in question is a Chesapeake bay Waterman. Sometimes he crabbing moving from pot to pot. In the fall he's patten tonging where the engine runs at or below 1,000 RPM for hours. He's probably never more than 20 miles from the marina and there are always other Waterman that will tow you in. For many Waterman, you can't fix it till it breaks. Most people on this forum don't put the hours on an engine in their ownership that he does in a year or two. The impeller certainly isn't going bad based on calendar years in service. Think there's a significant difference between age of the impeller and engine hours.

For myself, I'm torn between changing it when I see bits in my strainer and doing it as a PM. Part of the dilemma is the longer I go before changing it, the older the one I'm putting in is.

Ted

 

[C lectric]

I have a V555M. I change the impeller every 4-5 yrs. Never had a sign of trouble.
I install a brand new impeller, not a 3 yr old spare.
In that time I put on about 600 -800 hrs.

A lot depends upon how hard the engine is operated, how many hours yearly, and the condition of the old impeller when you do replace the existing unit.
I worked up to that interval by observation of the replaced unit.

I can JUST detect some stiffening of the vanes when I redo it. THey are NOT hard or stiff but compared to the new one they are slightly stiffer.

I won't go over that as further deterioration can often occur at an escalating rate.
This last year was at the 4 year mark as I was doing a bunch of other stuff and decided to re/re just because.

I normally run the engine at about 1800 revs. the ratio between the engine and the pump is about 2:1 so the impeller turns at 1/2 the engine rpm. or about 900 rpm or less.