Lost impeller blades

[callistov42]

Started up my 4jh5e Yanmar last Sunday and no water coming out of exhaust. Removed water pump cover and every blade on impeller gone. Replaced impeller, exhaust made water and we went from St Martin to Anguilla and back, no problems. I can not figure out how to open up Yanmar heat exchanger to try to find impeller blades. Do I need to? Westerbeke heat exchanger is easy (remove the ends). How do you get into a Yanmar heat exchanger?

[wingless]

Here is the specification sheet for the Yanmar 4JH4E.

On my engines, when the impeller blades break off, the bits are captured at the first heat exchanger.

When I replace the impeller, I also remove the raw water hoses from both ends of that first heat exchanger. I then use a garden hose to reverse flush the bits out of that first heat exhanger.

Then I gather all the bits for a "reassembly" to ensure all the bits have been retrieved.

[Vasco]

The blades are probably in the oil cooler at the back of the engine. Fairly easy to get at.

[Cheechako]

This a where a good pair of medical forceps comes in handy. Every boat should have them!

[shakey doug]

Take a look back down the inlet hose pieces also find their way down there.

[deblen]

Install a water strainer right after RW pump.

[Stu Jackson]

Originally Posted by deblen

Install a water strainer right after RW pump.

...or change the impellers more often before they disintegrate.

Your boat, your choice.

[MarkJ]

Originally Posted by Cheechako

This a where a good pair of medical forceps comes in handy. Every boat should have them!

Dont mention to your wife you are using her forceps in the oil cooler

[Akapeterc]

I just changed my impeller today and again discovered almost all of the blades were broken of, I got them all out of the oil cooler plus a few more as well as one large one in the intake area of the pump. It is only 10 months, 160hrs since I last changed and the last one was the same. Any ideas why I would be chewing up the impellers? In the manual it says to change every 1000hrs.


Sent from my iPad using Cruisers Sailing Forum

[Vasco]

Originally Posted by Akapeterc

I just changed my impeller today and again discovered almost all of the blades were broken of, I got them all out of the oil cooler plus a few more as well as one large one in the intake area of the pump. It is only 10 months, 160hrs since I last changed and the last one was the same. Any ideas why I would be chewing up the impellers? In the manual it says to change every 1000hrs.


Sent from my iPad using Cruisers Sailing Forum

Don't know your sailing area but does the boat sit on the bottom frequently or sail in waters with a lots of stirred up sand?

[Akapeterc]

It definitely doesn't sit on the bottom but I did touch bottom going over a bar recently. Sailing along the Australian east coast at present.


Sent from my iPad using Cruisers Sailing Forum

[undercutter]

Originally Posted by Akapeterc

It definitely doesn't sit on the bottom but I did touch bottom going over a bar recently. Sailing along the Australian east coast at present.


Sent from my iPad using Cruisers Sailing Forum

Sounds like your water pump may be worn out internally. Our Jabsco gear driven water pump on a Perkins engine would not last more than 40 hours of use before the impeller failed. Try either rebuilding or replacing the pump. If you rebuild be sure to replace all the internal parts including bearings, thrust washer and compression plate. I couldn't believe the amount of wear and tear that existed after comparison to the new pump.

Also impellers do not like to sit for long periods of time nor do they like to run dry as they overheat and become brittle. Make sure you have a good flow of seawater at the inlet head. Clean screens regularly and make sure thruhulls are not clogged.

[DougR]

Undercutter's comments about checking your water intake are important. Frequently excess depression on the intake side of the pump results in impeller blades being torn off from the suction. Make sure the thru hull fitting is adequately sized and not blocked, and the water feed to the pump has a minimum number of elbows ,etc.

Torn off blades is seen frequently on saildrive where the water passages in the drive are not keep clean.

DougR

[Akapeterc]

Thanks for all that information


Sent from my iPhone using Cruisers Sailing Forum