Re: [Amel Yacht Owners] Onan MDKKDP Heat Exchanger


Even when I'm not hooked up to shore power, there's a delay of about 10-12 seconds before the 220V shows up.  I was thinking about the motor running that long before the pump turned on, but really shouldn't be an issue.

I have one of those tools to remove the impeller.  My issue is the location of the impeller on the starboard side of the engine where I have to contort a bit just to reach it.  My back doesn't like that.

Speaking of impellers, I was helping Eric and Viki move their Omorphi Thea to a different marina for haul out.  She's a Santorin.  We were running a little late so I was motor sailing with 3/4 genoa and 3/4 mizzen in 20+ kt winds on the Chesapeake last week.  We were on a starbord tack hard on the wind.  A gust heeled us over a bit too far and we sucked enough air to burn up the raw water impeller on their Perkins.  In retrospect, I remember reading someone else's post a few years ago about the same thing happening.  Guess I'm not the sharpest tool in the shed, but got the impeller changed.  The wind lifted us and we sailed into Deltaville 20 min after sundown.

Happy Holidays to all!

From: "sailormon kimberlite@... [amelyachtowners]"
To: amelyachtowners@...
Sent: Monday, November 24, 2014 9:21 PM
Subject: RE: [Amel Yacht Owners] Onan MDKKDP Heat Exchanger

The generator has a transfer switch that switches from shore power to generator power after 10 seconds. This is so you don’t electrocute an electrician working on the dock while running your genset.
Yanmar has a new impeller that is threaded on the inside. They have a tool which is a bolt inside a nut that threads onto the impeller and you just have to turn the bolt and it pulls out the impeller.
Fair Winds
Kimberlite SM 376

From: amelyachtowners@... [mailto:amelyachtowners@...]
Sent: Monday, November 24, 2014 7:40 AM
To: amelyachtowners@...
Subject: Re: [Amel Yacht Owners] Onan MDKKDP Heat Exchanger
I didn't know that was possible, Alan. On Kristy, the generator doesn't start producing 220V AC until it had been running for about 10 sec.  I guess that's ok if you're not worried about the impeller burning up.  I'd like to hear more about this.
 Could the same concept be used on the Yanmar with a 24V DC pump?  The impeller on my Yanmar is much more difficult to get to.
SM 243
Fernandina Beach FL

On Nov 24, 2014, at 2:56 AM, divanz620@... [amelyachtowners] <amelyachtowners@...> wrote:
Yup, mine is the same , #437, and it is connected to the grounding system
BUT it still corrodes....mine needs a really good cleanup and the endcaps replacing.
The Onan is not a very well designed unit from a number of points of view...that heat exchanger in my view is too small, and the raw water impeller pump is terrible...chews impellers at 200 hrs or less...I'm going to replace it with a March 220V A/C centrifugal impeller to change...ever.
SV Elyse SM#437

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