Yanmar 3YM30 overheating

[RichardS]

Strange thing... I don't have it fitted on my Yanmar

I don't have one on either of my 3YM30s. It looks like some kind of anti-syphon break but I can't imagine why that would be on an intake as it would inevitable suck in air unless it was very "unsuckable" in which case, why bother.

I would remove it and see what happens.

Richard

 

[Catalina36]

Are you able to test the temperature of the discharged water, ie is the outlet reachable when you're under way?

If the water coming out isn't scalding hot when the engine is overheating then the heat exchanger isn't, umm, exchanging heat.

If the water is scalding hot then the exchanger is ok but there isn't enough water.

 

[jwilson]

Re Yanmar water pumps, even my local Yanmar agent admits the water pumps are rubbish. I am still meeting and hearing of owners of early 3YM30s that have never had the heat exchanger changed, because either they sail in a very cold water area or never run high revs. One day they will need the revs and find the engine overheating. It has put me off Yanmar for good - they should have contacted everyone and said - if your engine number is below 5xxx call our agent YYYY and have it changed. It would not have been that difficult because most of these engines were fitted into a few popular sailing yacht models, particularly from Jeanneau and US Hunter.

Current small Volvos have a similar known problem with a black box electronic part that again AFAIK Volvo have not publicised despite lots of engines breaking down because of it. Another to cross of my list of preferred engines .... A small sailing yacht diesel should not rely on electronics to run. If it has fuel and air it should go.

These days Beta and Nanni (based on Kubota blocks) or Vetus (based on Mitsubishi) seem to be the best small marine diesels.

 

[RichardS]

Re Yanmar water pumps, even my local Yanmar agent admits the water pumps are rubbish.

I always thought that the water pump used in the YM series was a standard Johnson F4B-903 which would have fairly widespread use so I'm not sure why it would be particularly rubbish in Yanmar engines.

Richard

 

[Catalina36]

Re Yanmar water pumps, even my local Yanmar agent admits the water pumps are rubbish. I am still meeting and hearing of owners of early 3YM30s that have never had the heat exchanger changed, because either they sail in a very cold water area or never run high revs. One day they will need the revs and find the engine overheating. It has put me off Yanmar for good - they should have contacted everyone and said - if your engine number is below 5xxx call our agent YYYY and have it changed. It would not have been that difficult because most of these engines were fitted into a few popular sailing yacht models, particularly from Jeanneau and US Hunter.

Current small Volvos have a similar known problem with a black box electronic part that again AFAIK Volvo have not publicised despite lots of engines breaking down because of it. Another to cross of my list of preferred engines .... A small sailing yacht diesel should not rely on electronics to run. If it has fuel and air it should go.

These days Beta and Nanni (based on Kubota blocks) or Vetus (based on Mitsubishi) seem to be the best small marine diesels.

An acquaintance of mine had a newly installed Volvo engine which developed a problem in the electronics which even the Volvo agent couldn't cure. In the end he wrote off what he'd spent on it and installed a Beta.