Rebuilding older Yanmar?

[Kello]

Originally Posted by massnspace

I am looking at some older sailboats from the 80s for extended coastal and quite possibly offshore trips.
If so, how much would one expect to pay? Are parts even available for such older engines? Any recommendations who could do the rebuild?
David
Seattle

Howdy David,

Currently in the midst of rebuilding a 30-y.o. Yanmar. The most “engine work” I’ve done before this is simple maintenance such as oil and coolant changes, servicing the heat exchanger, renewing the water pump">raw water pump, alternator, starter …

Except for recently having smoky exhaust, my Yanmar has never given me any trouble, so I *get* the “if it works don’t mess with it” mindset. But machines / their parts wear out and REQUIRE messing with to continue reliable operation. Good Old Machines were built for easy maintenance! And old Yanmar’s are no exception. Unfortunately modern society relies on “growth”, as in $elling $h!t, to “function”. One of the reasons I decided to rebuild my Yanmar Now, instead of when it isn’t working well, is because Yanmar has discontinued many parts my engine needs.

IMO: Some old boats are good. Some old engines are good. Computer chips and their complicated electronics are WAY overrated (you e- addicts will realize this when moisture/salt overcomes and/or the power goes out).


Shop for the boat that fits your needs, not by the engine it has. Yes, repowering can be a b!tch - my old boat’s engine bed was designed for a Perkins 4108 and I commend the guys who figured out how to install the Yanmar – not a perfect job but I couldn’t have done much better.

As for rebuilding an engine, if you have the aptitude and a CLEAN space to do so, then learn how to do it! Before I started my rebuild I was intimidated, but by reading many books and watching numerous YouTube videos I realized my fears were unfounded. I discovered that my old Yanmar is crazy simple inside, but it requires that everything be VERY CLEAN AND PRECISE.

“Old” technology is cool, computer chips are not. ”Liquor stores are essential” and young people (most everybody under 50) care more about their i-phones than their own life. You, your boat, your boat’s engine, knowledge, honesty, integrity, mean nothing to anybody anymore.
Check with your local Yanmar parts dealer before embarking on a rebuilding project. And only use Yanmar parts – anything less, such as on ebay, IS less. Only You can answer your questions.

[b.needalman]

The days when engines were reliably rebuilt are long gone. It costs so much today to do a good rebuild job that no one does that. Individuals try, but generally the result is less than great. the job requires a large number of specialized tools and skills.

Repower with a new Yanmar. Cheaper in the long run and reliability is guaranteed.

[argonauta1]

Depends on your concept for offshore sailing. I am a passage maker; my policy is if I cannot make 2 to 3 knots with the current wind, on comes the engine with enough RPM to give 5 knots. Following more or less this guideline we accumulated about 4000 hours during a ten year circumnavigation. Yanmar 4JH-2E. Hurst Transmission Model KBW 200 ratio 4.62. Yacht 1963 Beneteau/Moorings 445. New owner tells me the engine now has over 9000 hrs with no issues.

[j.g.evans]

I was stuck half way home with a Yanmar 3HM27 that would not start due to bad compression. The marina just happened to have a new 3GM30F coming in. New and 30 HP. I was able to install the new engine myself, but I wish I had put the old engine in a van and had the old engine rebuilt. The 3GM30F is not 30 HP, it is 24 HP. Every accessory is much lighter duty, i.e. the starter is 1/2 the size. I think all I needed was new rings and cylinders re-honed.
Consider running tests on your engine, i.e. compression, and have the injectors rebuilt. Then your engine may be good for several thousand hours.

[Elcapt]

Hi here is my 2c

I am second owner of a 36 yr old 2gm yanmar raw water cooled since 1992.

It has about 9500 hrs on it, it will burn a bit of oil running wide open for extended periods of time such as for 7-8 hrs

I replaced the injectors at around 4K hrs. And the cone in the gearbox gave up in Chile at around 7500 hrs . The drive plate has been replaced twice , once as precaution w new tranny .

Have replaced the exhaust elbow twice which is the Achilles heel of this motor
Easy job .critical component .

I would replace the injectors , the water pump and the exhaust elbow and the rubber belts .and the lift pump filter .maybe check valve clearance but it’s doubtful any adjustment is needed.

Take spare alternator , two spare fuel filter casting. Lots of spare fuel and oil filters
And five impellers. ( some of these come defective) and spare generator & water pump belts
And spare injectors. Rebuilt ok if tested professionally
Also a spare starter, although the little diesels are easily hand started if room for the hand crank

Make certain you have all the correct metric wrenches and sockets to work fast and accurate !

Yanmar 35 amp alternator may be too small:?

With some careful effort I replaced the alternator w 100 amp. This puts a big load on the motor to bring up a g 27 to full and requires a fully charged starting battery to avoid the charge load, once warm switch over to the g 27. Will take300 rpms off for a minute or two. No problems w this since 1999.

If this has been well maintained there is no reason to take it apart. Pulling and Re torquing the head on an aluminum engine requires super expertise and experience etc.

Some of the castings like the lift pump and filter etc are easily broken. Be very careful !

These are great motors , change the oil per specs and once you start it run it til it’s warm and never fear full throttle. A quick start and stop to get off a dock or anchor is the worst for a diesel . Good luck .

[Goodxcharly]

I would go with new. Nothing like a new motor for piece of mind which I think is what you are after.
A new motor adds value to your sailboat along with a way easier sale when that time comes.
A rebuilt is still a used engine.

[CuChulainn]

Originally Posted by massnspace

I am looking at some older sailboats from the 80s for extended coastal and quite possibly offshore trips.

Focusing on ones with Yanmars, as I have had good luck with them and some problems with other brands in the past.

But, it would be a 40 year old motor. Not sure I would want to go way offshore with that….

So. Would it be a good idea to buy a boat with such an engine, and immediately take it out and have it rebuilt before heading out? I have the time and tools to do the pull and reinstall.

If so, how much would one expect to pay? Are parts even available for such older engines? Any recommendations who could do the rebuild?

David
Seattle

I have an ‘86 C&C 33-2nwith the original Yanmar 2GM20F. Approximately 4 years ago, I had the engine rebuilt by a local shop; due to oil consumption issues. So new pistons, bearings, etc, etc. Cost about $4500 CDN and the engine runs like a champ now. I had wanted to buy a new Beta 25 hp engine but due to the configuration/engine box space available, the Beta would not fit. During this process I discovered that all the new engines I looked at; Yanmar, Beta. Sole etc now have the heat exchanger mounted on the left (port in the boat) hand side of the block as opposed to the right hand as with the Yanmar 2GM20F. Just something more to consider.

[rpackard]

The age of a Yanmar is not relevant compared to the number of hours and its past maintenance. My two-cylinder Yanmar from 1981 has low hours and runs and starts like new.

It is not true that beta parts are available easily. The basic kubota engine parts are available but the marinized parts, which are the ones that fail, are not easily obtained outside of the USA or England. You need to get them from Beta.

[Cat-a-tonic]

Old Yanmars from the 80's are simple and robust unless siezed for lack of raw water cooling. What is most likely to let you down at the wrong moment is the old 80's wiring and conections or dirty fuel.

[ClarkePrescott]

I have just gone through rebuilding a ‘92 Yanmar 4JH2-TE. I wouldn’t do it again. Expense was 2X cost of a newer non electronic engine.

[stormalong]

Originally Posted by rpackard

It is not true that beta parts are available easily. The basic kubota engine parts are available but the marinized parts, which are the ones that fail, are not easily obtained outside of the USA or England. You need to get them from Beta.

I have to disagree. My 20 year old Beta 50 with about 4500 hours on it has only needed a raw water pump rebuild and new engine mounts.

The pump rebuild parts were found on the internet easily. The engine mounts were available from several sources and surprisingly Beta had the best price. One very nice thing about Beta - even though they sell parts, Beta support from England was happy to provide the original manufacturer's name and part number for the engine mounts. Try getting that info out of Yanmar.

[JBsurfin]

Originally Posted by massnspace

I am looking at some older sailboats from the 80s for extended coastal and quite possibly offshore trips.

Focusing on ones with Yanmars, as I have had good luck with them and some problems with other brands in the past.

But, it would be a 40 year old motor. Not sure I would want to go way offshore with that….

So. Would it be a good idea to buy a boat with such an engine, and immediately take it out and have it rebuilt before heading out? I have the time and tools to do the pull and reinstall.

If so, how much would one expect to pay? Are parts even available for such older engines? Any recommendations who could do the rebuild?

David
Seattle

I have an orig '81 perkens 108 in my Dickerson, been all over with it and many a offshore trip. It still runs great. Parts always available. As posted by another, my mechanic says the same thing with diesel. If it runs fine, don't touch it.

[Ken of KC]

I think everyone has their own comfort zone. What is right for me is not right for you. I would first take a deep look into what you have. 40 years you probably don't have a good source of it's history, maybe it's been rebuilt. There is nothing in what you have said that would motivate me to change it. I think we get in too big of a hurry to throw money at it for my money I have to have a reason to spend it. How does it look, clean and well maintained? Rusty piece of crap? Do you know how many hours on it? Usage history? More diesels are prematurely worn due to just sitting than actually worn out. Does it start well? Smoke? White, Black or White? Does is use oil? If you want to know what you have here is what I would do. Next oil change do an oil sample test and have it analyzed and see what is going on in there. Do and injection pump spill test and see what this shows, even flow etc. Next maybe check the glow plugs look them over well, test them. Next have the injectors tested. Proper break pressure? Leak down test? Pattern test? If it checks all the boxes I would not open it up. But I would bet you will find some things weak, most likely injector pattern and leakage. I think now and only now do you have the information to make the correct decision for you. Just changing to say a Beta and they are a great little engine makes different issues and problems and you may or may not be better off. If you do find a reason to change, for me, it's a no brain er. Unless I have major hard part issues upon tear down and inspection I rebuild. You save a lot as you don't have to buy castings, cranks etc., with a replacement you buy a lot of things you don't actually need. So I would make sure that I actually need a new engine. The most problematic things can be injection pump and injectors, water pumps and ancillary parts as well. That's just my two cents.

[nofacey]

I wouldn’t rebuild or replace your engine due to its age……what are its hours, and condition?

Go get someone that does mechanical surveys (usually an old engine guy) and get him to do an evaluation. You may need to do nothing more than ensure the fuel is clean!

[lifeofreilly57]

If your paying a shop or mechanic to rebuild the engine the economics may not work out.
I rebuilt a Universal some years ago and yes they are Kubota small tractor engines with a different air cleaner and a marine heat exchanger fitted. I knew the owner of a Kubota equipment dealer at the time, the same parts from that shop were substantially less than the marine Universal dealer, you just need to identify the motor by cross reference. Any motor labeled marine will carry a price premium for parts, unless you can cross reference the base motor to its original application.
I rebuilt my Perkins 4108 6 years ago and found it quite affordable compared to some other motors I've rebuilt, all tolld, $2000 for parts and a distribution pump rebuild. But, paying a mechanic or machine shop to do the work would now put you in the same economic range of buying a rebuilt engine from a reputable dealer that comes with a warranty.
Swapping to a different engine will incur other costs related to installing it in your boat, such as adapting it to your current transmission, cooling system and electrical connection, usually you'd have to go with that manufacturers engine control panel and adapt the alternator to the current charging system. Also the cooling hoses, etc, etc.
If you repower with a larger engine it may also require changing props or the transmission. Some low rpm motors came with direct ratio transmissions, higher rpm engines had reduction transmissions, like the Velvet Drive transmission in my boat. Most boats of that era either had Velvet Drive or Hurth transmissions, but some European and Japanese engines had less common transmissions.
I understand your concern, buying a 40 year old boat without knowing the maintenance history of the systems is a roll of the dice. Trying to repair or replace an engine in another country can be painful, just getting parts is painful enough, finding a good, reliable mechanic is like finding hens teeth.
Tacking up a narrow channel with reefs on both sides may sound like the macho thing to do, but not the smart thing to do. I've had to do that on our 47 foot monohull due to a contaminated fuel fill, my wife still torches my shorts over that one, had my butt puckered tight enough to pull the wrinkles out of my face. In a small boat that points, no problem, in a bigger cruising boat that doesn't point like a racer cruiser it's a whole nother story.