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patrscoe 09-12-2011 04:00 PM

Rebuilding Yanmar 3GM30F; need advise $?
I recently started restore and modify our P35. My first phase and a major scope on my list is her Yanmar 3GM30F with 3300 hours. It runs well, starts up within a few seconds but hours don't lie and after all the work I am putting into this sailboat, last thing I want is for the old tired engine to fail next year.

I am not going to purchase a new Yanmar and my intention is to hire a professional mechanic for the complete rebuild.

I am currently getting two quotes, one from our marina shop and another one from a marina down the bay.
How much should I expect this will cost so that I can evaluate the proposals?
Any recommendations on good reliable mechanics in the Deltaville, Va and surround area?


SecondWindNC 09-12-2011 04:44 PM

I think you may be jumping the gun with completely rebuilding a running Yanmar at 3,300 hours. The life expectancy of a well-maintained marine diesel can be well upwards of 5,000 hours (sometimes more like 8k-10k). Have you had problems with the engine that have led you to this?

I would suggest doing an engine survey instead. Have the compression tested, injectors tested, etc. Fluid (oil and coolant) samples can also reveal a lot about the engine. I'm sure there are some mechanics in your area that do engine surveys. Address any problems that the survey identifies, and go on enjoying your boat.

The Life Expectancy of the Marine Engine -

patrscoe 09-12-2011 05:00 PM

Right now I am asking for pricing on both, engine rebuild and a complete survey of the engine and recommendations. I believe the engine was taken care of by the previous owner and I had a minor survey completed when I bought the sailboat which included testing the oil.

I read that Yanmar with 3500 to 4000 hrs are about the limit before major repairs are required or rebuild.

JimsCAL 09-12-2011 05:50 PM

I'm with SecondWind about doing a complete survey first. If the compression and oil analysis check out, I would be reluctant to tear it apart to do bearings, rings, etc. Can't argue with rebuild/replacement of injectors, pumps, starter, alternator, etc. as those are the things that are most likely to cause issues down the road.

saillife 09-12-2011 05:57 PM

Gotta agree with secondwind on this. My Yanmar 3GMF was 28 years old before I had a rebuild done. I don't know what the hours were on it. Didn't have an hour meter installed originally. I had mine rebuilt this past winter after I trashed a piston ring two years ago (overheating). Yes the engine key does hang on the raw water intake now!

Even with the bad ring, I ran the engine for a year, it just smoked, _a lot_, until it warmed up and than it ran fine. Yanmar is a good diesel. Like the saying goes 'If it ain't broke, don't fix it'.

Finally, as to costs, I paid $650 for parts. I still haven't gotten the labor bill from my mechanic, he's infamous for being bad about getting bills out. His original estimate was for 1.5 - 2k for the job including parts. I believe this is a very good price.
Good luck,

patrscoe 09-12-2011 06:17 PM

Hopefully the complete survey comes back with great results. As noted earlier, I have read that 3GM30F had a life span of about 3500 hrs.
Could you recommend list of items that makes since to rebuild / replace i.e. injectors, pumps, starter, alternator, etc... per Jim's comments? Seems like everytime I turn around their is a issue like a leaky fuel line so I had the fuel line assembly replaced and then our previous Marina had to move the sailboat to do a quick haul out and they turned off the raw water seacock... didn't know this until I went out and the high temperature alarm went off. Lesson learn there, always... check for engine cooling water coming out the exhaust before leaving the dock.
Thanks for all your advice.

mitiempo 09-12-2011 06:22 PM

A fresh water cooled diesel should last much longer than 3500 hours as long as it is maintained properly - Yanmar, Westerbeke, or any other major brand.

Without salt water in its veins it's just getting broken in.:D

patrscoe 09-13-2011 11:06 AM

Everyone here was right on the mark. My mechanic called me this morning and stated that the Yanmars are merely bullet proof and unless it starts hard and you see smoke at cruising rpm(s), no overhaul should be done. If maintain, you can put 5000 hrs on them.

It was recommended that we pull the engine this winter which I have agreed to. Going to replace the engine mounts (collapses), replace the water pump, belt, complete tune up, adjust the valves, replace the alternator and starter, wash engine and repaint, etc... basically going through the engine from top to bottom. This will also give me a good base line for maintenance and give me a chance to replace the hoses in the engine compartment (as needed), go through the shaft and drive train, secure the loose wiring, and clean up / paint the engine compartment.

By the way, two budgets received to date completely overhaul the Yanmar engine was $6,000 to $9,000. (ouch!!!) Everything I am talking about above will costs $2,000 to $2,800.

JimsCAL 09-13-2011 11:34 AM

Sounds like a plan! Good to hear the advice here was helpful.

schoonermaster 04-18-2012 07:14 PM

Re: Rebuilding Yanmar 3GM30F; need advise $?
A completely rebuilt 3GM30F can be had for $5,500 if you have a core, and that's a RETAIL price.

You need to be careful with that term 'rebuilt'. It will pay you to ask for specifics on what is meant by 'rebuilt' since the term is subjective. In my world, 'rebuilt' and 're-conditioned' are two very different scenarios.

Rebuilt should mean returned to factory specifications in ll respects. You should get a written warranty without asking on a 'rebuilt' engine.


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