Hunter 41DS Yanmar Engine Damage

[Second Wind21298]

Hi:

I plan on purchasing a Hunter 41DS but I would like to know if any other 41DS owners had issues with their exhaust system and had water somehow re-enter the engine via the exhaust hose. One 2007 41DS owner had his Yanmar engine replaced because of it in just two years of service. Is there a service bulletin to inform folks of this issue and possibly re-route the exhaust system so this does not happen or was this just a bad install on that particular boat?

Thanks,

Ray

 

[oschulz]

I bought a 2007 41DS a couple of months ago. Engine was replaced last year because of the issue you report. New exhaust with high elbow was installed this time. I read somewhere in the manual that came with the boat that this was an option when new. Sounds like this may very well have been a design flaw and what they considered an option should have been standard equipment.

 

[Rick486]

When I purchased my 44DS new the exhaust was plumbed below the water line. I didn't like that so I went on a tour of boatyards to check other late model Hunters to see where the exhaust exited the hull. Guess what? There was no consistent pattern apparent. Some were above, some below. So I had the dealer install a conventional exhaust fitting in the waterline stripe which is well above the water line, and a high loop just inboard. Works fine. No worries.

 

[ice breaker]

I bought a 2007 41DS a couple of months ago. Engine was replaced last year because of the issue you report. New exhaust with high elbow was installed this time. I read somewhere in the manual that came with the boat that this was an option when new. Sounds like this may very well have been a design flaw and what they considered an option should have been standard equipment.

Do you have a picture of the new elbow installation?

 

[oschulz]

No pic with me. Will take one this weekend and I'll post it.

 

[oschulz]

No pic with me. Will take one this weekend and I'll post it.

here's a pic

 

[Don Lucas]

I fail to see how that little extra raiser section is going to made much difference

I know on my 410 the exhaust run along the hull under the berth there loops way up in the aft locker before going back to the waterline. Are people saying the 41DS exhaust just runs from the engine to waterline with no loop?

 

[SEMPERAVANTI41]

View attachment hunter08_41.pdf

Ray,

I have attached an options list for the 41DS from 2008. There is no option for a "high" riser on the exhaust. I think what is critical is the height of the exhaust hose, not the height of the exhaust elbow. On my boat the exhaust hose is carefully routed as high as possible under the starboard aft compartment, behind the the aft cabin. The seawater that is injected at the exhaust elbow only has to fall to the waterlift muffler when the engine is shut down, as it is under pressure when the engine is running. As the picture shown in this thread shows, the elbow is as high as possible as it has to fit under the aft cabin vanity. After the waterlift muffler, the water flows under pressure to the top of the exhaust loop and then falls out the thru hull.

I have had my boat 5 years and have had no issues with the engine. Also I have closely examined the whole exhaust system on my boat and have found no shortcuts or poor design. By the way, I would purchase my boat again and am proud to own it.

 

[kloudie1]

The crucial part is that the water lift muffler has to have enough volume to contain the water coming down the aft exhaust hose high loop after engine shutdown. It helps to have a high vented loop in the water line from the heat exchanger to the elbow.
http://www.westmarine.com/WestAdvisor/Exhaust-System-Basics

EDIT: oh yeah...and the elbow can't have holes corroded through the "uphill" side of its internal water jacket