Impeller on Volvo D3 150

[Flats]

Well I committed the error that I have always avoided for the last 20 years. I checked twice before starting and failed to open the thru hull for the engine and obvious senior moment. Needless to say the engine overheated and I shut it down as she stalled. Opened the thru hull, let the engine cool for 30 minutes. restarted the engine, got water from the exhaust and motored back to my mooring which was less than a mile away. On the way backThe temperature continued to drop after the was in the 175 +_ 2 range during the short motor back. Now to my questions.

At a minimum I need to check the impeller and probably replace it. Correct?

Kenny Mars has a video that makes the process of replacing/ checking look very straight forward. Loosen the tensioner. Remove 4 bolts, pull out the impeller, check or replace. Kenny has deep experienced and works on RT’s all the time, so what may be easy for him, might not be so easy for a mere mortal like me. Has anyone else replaced the impeller on their D3 in a RT 25. Is it as straight forward as Kenny make is look? I would really like some input from the community.

We bought the boat last fall. I built a spare parts kit with parts ordered from RT so I have an impeller in hand. I also have the tools needed to do the job in my onboard took kit.

Experience and advice is appreciated.

Bob Flaherty
Scituate, MA
Muirgen - RT 25

 

[BB marine]

D-3 impeller is easy to replace. It is a bit tight to get to R25. When you said you operated the engine until it stalled? Do you mean when it went into derate because it overheated to alarm and derate? If this is the case you should be ok. Derate is at 208F which is not going to damage the engine for a few minutes of run time. If you shut it down when it was going to stall out that would be much higher temperature. I would inspect the integrity of the exhaust hose. The silicone hose and is not designed to be run with dry exhaust. It will degrade from high temp. There are several threads about changing the impeller in a R25. I will advise running the engine with fresh water flush before doing the impeller change if this is not possible use rags to protect the water pump belt tensioner from getting contaminated with salt water. if it gets saltwater into the spring it will lock up. after replacing the pump impeller spray the belt tensioner with a penetrating oil and exercise the spring this will work the the penetrating oil into the spring and bearing to help lubricate it. I know of many D3 owners that found out the hard way about this. The sad part about this is it is usually service technicians doing the work!!! Just my opinion!

 

[Flats]

Brian,

Thanks for the reply. Then engine alarm was active and the engine was slowing when I shut her down. The instruments showed the engine temp of 192 when i did this. Given that the engine did not overheat on restart and stayed in the 170 range when i drover her back to the mooring. Do you believe that i need to inspect / replace the impeller. Could it have survived the incident given that It remained in usual range. I drove back at < 1000 rpm>

Thanks for the advice.

Bob

 

[Flats]

Brian,

Thanks again, I have answered my last question. I am replacing the impeller. Better safe than sorry.

Regards,

Bob