Yanmar 4by2 180 info

[Grith]

Hi Guys ( and Girls )
Sorry to bust in on your forum as a non forum boat owner and a bit of a weird one at that having an Imexus 28 Trailable Yacht.
I have been really struggling to find knowledgeable boaters with experience on the Yanmar 4by2 180 and also the ZF350 Leg.
In googling re this engine I stumbled across discussion on your forum and given my yacht ( I know, cover head in hands ) has this engine leg combination fitted I am appealing for help.
No one in Australia seem to want to discuss this engine as it just isn't normal to see one of these in a yacht never mind a trailable yacht and I thought I would appeal for some help here.
My 2011 engine and yacht have seen very little use by the prior owner with only 20 hours on the engine. On my first major live on board trip, as distinct from the previous very short ones out to the start line at my club, my engine was heading towards overheating when I shut it down at 99 degrees after about 15-20 minutes use.
Upon investigation my sea water impeller is in pieces when I pulled this apart and Yanmar tells me they need to be changed out every year which seemed excessive to me. Any thoughts?
My engine draws its sea water in through the Yanmar ZF350 Leg which initially the Australian distributor for Yanmar told me that wasn't possible only to correct himself ( somewhat embarrassed ) later that day.
This probably gives you some idea of even the distributors level of expertise on this engine and this leg combination.
How long do you guys think the sea water impeller should last with regular service and what would be your thoughts/recommendations?
I have the electronic throttle control NMEA linked system and cable to power hydraulic wheel steering and hydralic leg control as well and don't know what is on your boats .
Any advice around service life, tips and tricks or anything around these engines from knowledgeable people would be sincerely appreciated.
Kind Regards
Graeme Smith
Kangaroo Valley New South Wales Australia.

 

[BaylorU]

Hey Graeme! Welcome to the Board.
In my experience, it’s often acceptable to go more than a year, but I’m not really sure I’d ever want to go more than about 2, especially in salt water. Of course, this depends on use....if you’re putting on 500 hours a year, then you’re obviously not going to go as long as if you’re putting 50 hours a year on the boat.
I think after 2 years the concern isn’t just hours, but the rubber impeller breaking down due to the elements.
So, in summary, there is likely a maximum service life in hours (which I’m sorry but I don’t know....someone else surely will), and a service life in years (Yanmar may recommend a year, but I think 2 is acceptable....I’m sure others will disagree and that’s fine....I can always learn more).
Hope this helps!
Ken

 

[YukonRon]

Hi Graeme, welcome.
We have the Yanmar 4BY2-180 in our 2113 R25. The Yanmar manual Periodic Maintenance schedule recommends to change the impeller every 250 hours or 1 year, whichever comes first. I think the general consensus is to change it every year regardless of hours if the boat has been sitting unused through the off-season, because the rubber impeller vanes can take a set and stay bent after being that way all winter. Access to changing the impeller can be a real pain in our boats, but most would agree they would prefer to do it in the yard or at the dock rather than at sea in a storm after failure. Also, if you have had an impeller go to pieces, you should take the heat exchanger apart and fish out all the pieces as they will be blocking your cooling tubes. Personally, I would much rather change the impeller proactively than go through the hassle after failure.

 

[rpmerrill]

I would agree mostly with YukonRon. My engine had about a thousand hours on it when I got it. The previous owners were big ICW cruisers. I'm doing about a hundred hours a year. First impeller change was done by a mechanic when I first got the boat. After three summers I changed my impeller myself this fall. It would not be a difficult job except for issues unique to our boat. My old impeller came out in beautiful condition. No real wear, brittleness or missing pieces. I think, for me, every two years should be way safe. (Not looking forward to the day I have to check the heat exchanger, however.)

There is another issue with the Yanmar regarding grounding of the oil pressure sensing system. I never had the problem. I did have a sender go bad whereby it would measure higher pressures on start up ok. But then as it warmed up and the actual pressure went down the pressure reading would suddenly jump to 100 plus psi. Problem was the thousand hours running at those lower pressures. It is a sliding contact rheostat that supplies the resistance to the computer. The slider wears out and the resistance goes infinite... thus a high pressure indication on the panel. Easy fix but an expensive part from Yanmar.

BTW, should mention if you are running in warm tropical waters you will run some pretty warm engine temperatures. I have noticed the effect on my temps from spring to summer to fall.

Spent a week on business back in the 90's in NSW and also Mt Isa. Quite a place!
Good luck.

 

[knotflying]

As far as what happened to your impeller, I suspect that because of lack of use it deteriorated and broke up. On our boats the impeller is rather difficult to get to and inspect. Once you have opened up the pump to inspect, you may as well replace it. You boat may be easier access so inspecting and using the same impeller may work for you. As mentioned earlier there were a couple of service bulletins, one was for grounding of the oil sensor unit, another was for upgrade of the software and it was related to oil pressure fluctuation, another was the replacement of the oil line type that went from the oil line banjo fitting to the oil sensor and then another replacing the coolant lines coming off the engine and then tying into the hot water heater. Depending on year of engine all may apply.

 

[Grith]

Hi All Thank you for the info. Yes I am also concerned about my heat exchanger having found the impeller arms almost completely disintergrated. Thanks for the feedback and info. Has anyone successfully back flushed or cleaned out the heat exchanger that can give some advice.
By the way I am on a Trailer Sailer discussion group run on a platform run by the same crowd that allows photos to be attached to posts but cannot figure out how to do this on this platform. Can you do that here and if so how.
Regarding reaching the impeller pump for service I have to remove the rear fire wall behind my low roof height transverse double bed under my cockpit and crawl in to the engine bay but have seen much worse in my time in boating.
Regards Graeme