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08-12-2018, 16:37
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#1
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Registered User
Join Date: May 2010
Location: Mornington Peninsula, Melbourne, Australia
Boat: Seawind 1160, 38 foot
Posts: 126
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Rebuild or replace
Hi all
Question re the cost of rebuild/reconditioning of Yanmar 4JH5E motors. Over 5000 hours and ready for something to happen. Can I please have your views on the cost to rebuild/recondition these two motors versus replacing them entirely. There will be a cost gap I believe but I don’t know what it it right now.
Mick
__________________
Fair winds - Mick
When all you have is a hammer everything is a nail!
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08-12-2018, 16:46
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#2
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Registered User
Join Date: Oct 2015
Posts: 2,007
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Re: Rebuild or replace
Quote:
Originally Posted by Mick C
Hi all
Question re the cost of rebuild/reconditioning of Yanmar 4JH5E motors. Over 5000 hours and ready for something to happen. Can I please have your views on the cost to rebuild/recondition these two motors versus replacing them entirely. There will be a cost gap I believe but I don’t know what it it right now.
Mick
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Are there symptoms that would indicate you are near the end on these engines?
I once asked a mechanic about rebuilding a 30 year old engine with 6,000 hours on it. His answer: "These need a rebuild between 6 and 12 thousand hours. It might go another 15 years. Why rebuild it if you don't have to?" I sold that boat 10 years later with 9,000 hours on the engine--still running like a top.
I now sail a boat with 8,000 hours on the engine, and 7,500 on the genset. Compression is good, they run smooth and happy, and output full power. Why would I throw them away?
But... if it is time to overhaul them, I'll give you the two answers you will get here: 1.) Rebuild them, it's cheaper. 2.) Throw them out, rebuilds never run right.
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10-12-2018, 14:16
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#3
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Registered User
Join Date: May 2010
Location: Mornington Peninsula, Melbourne, Australia
Boat: Seawind 1160, 38 foot
Posts: 126
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Re: Rebuild or replace
Quote:
Originally Posted by billknny
Are there symptoms that would indicate you are near the end on these engines?
I once asked a mechanic about rebuilding a 30 year old engine with 6,000 hours on it. His answer: "These need a rebuild between 6 and 12 thousand hours. It might go another 15 years. Why rebuild it if you don't have to?" I sold that boat 10 years later with 9,000 hours on the engine--still running like a top.
I now sail a boat with 8,000 hours on the engine, and 7,500 on the genset. Compression is good, they run smooth and happy, and output full power. Why would I throw them away?
But... if it is time to overhaul them, I'll give you the two answers you will get here: 1.) Rebuild them, it's cheaper. 2.) Throw them out, rebuilds never run right.
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And I guess there is my problem, conflicting advice re the time to rebuild. I hear 5000-7000 and I hear 6000-12000 (a lot of different mechanics views out there). The motors are ok, no obvious black smoke, wheasing or any of the usual symptoms. But I don’t want to be transatlantic and have them die on me. The problem is risk management for me.
So I’m still trying to understand the costs involved.
__________________
Fair winds - Mick
When all you have is a hammer everything is a nail!
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10-12-2018, 22:50
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#4
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Registered User
Join Date: Apr 2007
Location: Australia
Boat: Island Packet 40
Posts: 6,415
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Re: Rebuild or replace
6,000 hours is about 250 days running time. I know the loading regime is different but if you were running these engines on a genset you would expect to get 2 or 3 years service out of them before requiring an overhaul. They are barely run in and I would not mess with them.
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10-12-2018, 23:05
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#5
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Registered User
Join Date: May 2010
Location: Sydney Australia
Boat: Fisher pilothouse sloop 32'
Posts: 3,413
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Re: Rebuild or replace
Quote:
Originally Posted by RaymondR
6,000 hours is about 250 days running time. I know the loading regime is different but if you were running these engines on a genset you would expect to get 2 or 3 years service out of them before requiring an overhaul. They are barely run in and I would not mess with them.
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My sentiments exactly, if in doubt have a compression test done and an engine survey by a REPUTABLE engineer.
__________________
Rob aka Uncle Bob Sydney Australia.
Life is 10% the cards you are dealt, 90% how you play em
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10-12-2018, 23:11
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#6
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Registered User
Join Date: Feb 2016
Location: Canada
Boat: T37
Posts: 2,336
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Re: Rebuild or replace
If the history is unknown or suspect lack of maintenance and want to give it a good go over just do the top end. It’s like giving a smoker a new set of lungs, can help avoid costly repairs or situations down the road, give you a chance to replace bolt on parts if needed, replace hoses, gaskets and tighten bolts that may have loosened and so on. Almost all breakdowns are due to lack of regular maintenance.
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10-12-2018, 23:42
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#7
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Registered User
Join Date: Apr 2013
Posts: 11,002
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Re: Rebuild or replace
You've provided no indication of a problem.
If it's ain't broke, don't fix it.
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11-12-2018, 13:42
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#8
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Registered User
Join Date: Jan 2007
Location: Brisbane after cruising (Atlantic -> Med -> Carib -> Pacific)
Boat: Vancouver 36, Hobie 33, Catana 48, now all with new owners
Posts: 364
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Re: Rebuild or replace
Quote:
Originally Posted by Mick C
And I guess there is my problem, conflicting advice re the time to rebuild. I hear 5000-7000 and I hear 6000-12000 (a lot of different mechanics views out there). The motors are ok, no obvious black smoke, wheasing or any of the usual symptoms. But I don’t want to be transatlantic and have them die on me. The problem is risk management for me.
So I’m still trying to understand the costs involved.
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The nice thing about a catamaran is you have two, so if one dies, you are still fine, and can carry on until it is convenient to get the broken one fixed or replaced. Makes the risk equation a little different than if you only have one engine. Of course there is still the factor to consider of convenience and cost of rebuild at home v cost of repair while cruising.
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11-12-2018, 14:27
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#9
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Marine Service Provider
Join Date: Sep 2014
Location: Fairlie Scotland UK
Boat: Southern Cross 31
Posts: 160
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Re: Rebuild or replace
I started off as a trainee mechanic when I left school, and although not in that industry today, I have worked with engines all my life, what I have always found with marine engines, is that they rust out, they don't wear out, I have seen a lot come to the end of there lives due to rust, but not wear, have opened engines with huge amounts of hours on them, and not even a lip at the top of the cylinder. But have seen some serious rust damage on the outside, even sumps rusted through, hose ends, ancillary parts, alloy parts so badly corded that they have to be replaced, even saw an outboard motor with alloy head corroded right through, due to the sea water cooling. I would leave your engines.
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