Impeller blades gone

[Aadudley]

At haul out this past week I pulled the impeller housing on our 25sc to replace the old impeller with new. To my surprise the old impeller had most of the blades missing. The boat temperature the day I pulled it never got above 180 and I have no idea when this could have happened. So my question is this: Will those impeller blades flow thru the heat exchanger or can they cause an obstruction that may impede water flow? If there is a chance of impediment what should my next plan of action be be?

What amazes me is after engine start up I religiously check the exhaust for water flow and had no problem at the time. Took a 15 minute ride to warm up the boat oil for seasonal changing and then pulled it for the season. I'm guessing we had an intake obstruction during this time.

Thanks for any info anyone has.

 

[Red Raven]

If you have the Volvo D3 there are two places to look for impeller particles. The first is the main engine heat exchanger input. Port side of the engine near the aft top. Pull the hose and check for particles. The second, assuming small bits made it through, check the Input of the intercooler on the turbo on the starboard side. Follow the path of the raw water hose from the engine heat exchanger. Pull the raw water hose and check for particles. It is not a difficult check. Just hose clamps.

Curt

Edit: Change “three” to “two” in the first sentence. The reverse gear cooler was the third place I was considering but dropped it from the rest of the text when I remembered it is in the flow before the raw water pump.

 

[nzfisher]

It is helpful to keep the old impeller. I had the misfortune of the same issue and was able to recreate the old impeller with the recovered pieces. Good to confirm they were recovered. On my boat, a Yanmar, virtually none of them washed through the system. Almost all of the pieces were recovered in the reconstruction. I made a tool to assist in their recovery. If you have a Yanmar I would be happy to share the process of recovery although it is buried somewhere in earlier posts on tugnuts.

 

[CAPTCRUNCH]

If you have the Volvo D3 there are three places to look for impeller particles. The first is the main engine heat exchanger input. Port side of the engine near the aft top. Pull the hose and check for particles. The second, assuming small bits made it through, check the Input of the intercooler on the turbo on the starboard side. Follow the path of the raw water hose from the engine heat exchanger. Pull the raw water hose and check for particles. It is not a difficult check. Just hose clamps.Curt

That's helpful information, but isn't that just two places? Did I miss one?

 

[Red Raven]

Sorry, only two places the pieces can collect. The third place I was originally going to describe is the reverse gear cooler. Then I remembered the reverse gear cooler is located in the flow prior to the raw water pump so it cannot capture loose pieces of the impeller. I forgot to update my initial sentence. I have now changed three to two in that sentence.

NZFisher’s idea to keep all the parts found is a good one though I suppose pieces small enough to get through the heart exchangers would be ejected out the exhaust and thus would be unaccounted for. Perhaps small bits missing could be ignored.

Curt

 

[CAPTCRUNCH]

RR- Got it. Thanks. - CC