Yanmar 2GM20 full of salt water

[webcraft]

a) becoming increasingly difficult to start, plus oil leak getting worse

b) eventually will only start after spinning with decompression levers back for a couple of seconds

c) after 2 hours on passage starts to sound a bit rough then revs die and it stops

d) after sailing for 7 hours attempt restart. Starts but will not rev and dies as before

e) water in oil, lots of it. Oil/water emulsion flows out of dipstick hole as if under pressure.

f) exhaust elbow also full of water

g) head gasket shows signs of having gone, water everywhere

Engineer recommends a complete rebuild. What does the team think the likely sequence of events leading to failure was?

- W

 

[robmcg]

Exhaust flooded?

 

[garymalmgren]

Engineer recommends a complete rebuild. What does the team think the likely sequence of events leading to failure was?

a complete rebuild. Yep. Unfortunately, that's what you are in for.
BUT It can be done affordably. Thee following vid is a pretty comprehensive guide to the job.

the likely sequence of events leading to failure was? Without any real information to go on, I would say age, along with a lack of careful maintenance and a bit of bad luck.
You will find out when you strip it down.

Best of luck.
gary

 

[earlybird]

[QUOTE.

Engineer recommends a complete rebuild. What does the team think the likely sequence of events leading to failure was?
[/QUOTE]
Progressive, eventually serious failure of the head gasket seems a like a likely basic reason. I'd start by removing the head to reveal any horrors. You might be very lucky, but you will have to face up to possibly damaged pistons, injectors etc. even a bent con-rod if your lucks really out. A complete, expensive re-build might be avoidable though.

 

[TernVI]

Is this a raw water cooled motor?
If so, then simple gasket failure will do it.

I wouldn't bother rebuilding it. It will be very expensive to do properly and it will still be an old engine when you've finished.
Either do some checking and then do the minimum to get it working again (could just be a new head gasket) or replace it.
It's a slippery slope to spending a lot more than it's worth, and taking months to do so.

I would only get engines rebuilt by either myself, or someone with a very good reputation, who basically did nothing much else.
I'd know where to go to get my bike engine rebuilt good as new or better, but wouldn't be sure with a Yanmar.

In the short term, get it clean dry and oiled, it may have some trade in value to a rebuilder.

 

[RichardS]

The most common reason for head gasket failure is engine overheating. However, the actual overheating episode could be months or even years earlier depending on how much the engine is used. How long have you had the boat? The failure might have been started by the previous owner.

I'm not sure what exhaust elbow full of water means. The water should drain down into the water trap. It sounds as if the elbow, or something, is blocked and that could also have caused cylinder problems.

You will know the extent of the damage once the head is off and it might just be a simple head skim and gasket change but if there is damage to pistons/bores/bearings etc then I would probably replace the engine for a new YM series one if the mounts are the same, depending on how old it is.

Richard

 

[[2574]]

Exhaust flooding could be due to repeated engine cranking without engine start?

 

[bluerm166]

I had this exact thing happen with my 30 year old 2GM20.It was impossible to tell where the interchange had started.I had decoked the injection bend over the winter (but not then pressure tested it) ,and there was a track across the head gasket ,but possibly while creeping back on one cylinder to a point where sailing became possible the main bearings were shot.So I'm pleased that I installed a new Beta and count my lucky stars that the demise of the old engine didn't happen off the continent.

 

[webcraft]

Exhaust flooding could be due to repeated engine cranking without engine start?

Yes, this may have contributed. I eventually had to resort to spinning the engine with the decompressors open for a few seconds to get it to start. But it then ran for an hour and a half's motor sailing before it died, so not sure.

However, the head gasket is definitely shot and probably has been going for some time, leading to the difficult starting and the oily incontinence.

- W

 

[Stemar]

A replacement, while always likely to induce fibrillation of the wallet, may be simpler and not necessarily a lot dearer.

Don't know if these guys have anything - Engine For Sale Marine Enterprises Ltd, Dorchester

Alternatively there was a company selling Chinese marine diesels at well under normal marine prices that got some favourable comments here a year or two back. Don't know if they're still around.

 

[webcraft]

I had this exact thing happen with my 30 year old 2GM20.It was impossible to tell where the interchange had started.I had decoked the injection bend over the winter (but not then pressure tested it) ,and there was a track across the head gasket ,but possibly while creeping back on one cylinder to a point where sailing became possible the main bearings were shot.So I'm pleased that I installed a new Beta and count my lucky stars that the demise of the old engine didn't happen off the continent.

Yes, sounds similar.

I would love to fit a new engine, but we have limited funds and a guy I trust to do the rebuild affordably and cheaply, for less than half the cost of a new engine. He will not rebuild it unless he thinks we will get a decent engine as the end result.

- W

 

[Dan Tribe]

a) becoming increasingly difficult to start, plus oil leak getting worse

b) eventually will only start after spinning with decompression levers back for a couple of seconds

c) after 2 hours on passage starts to sound a bit rough then revs die and it stops

d) after sailing for 7 hours attempt restart. Starts but will not rev and dies as before

e) water in oil, lots of it. Oil/water emulsion flows out of dipstick hole as if under pressure.

f) exhaust elbow also full of water

g) head gasket shows signs of having gone, water everywhere

Engineer recommends a complete rebuild. What does the team think the likely sequence of events leading to failure was?

- W

a) becoming increasingly difficult to start, plus oil leak getting worse

b) eventually will only start after spinning with decompression levers back for a couple of seconds

c) after 2 hours on passage starts to sound a bit rough then revs die and it stops

d) after sailing for 7 hours attempt restart. Starts but will not rev and dies as before

e) water in oil, lots of it. Oil/water emulsion flows out of dipstick hole as if under pressure.

f) exhaust elbow also full of water

g) head gasket shows signs of having gone, water everywhere

Engineer recommends a complete rebuild. What does the team think the likely sequence of events leading to failure was?

- W

I had exactly the same symptons on my 2GM.
A top end overhaul and new head gasket did nothing to improve matters.
I asked the yard engineer who diagnosed probably corrosion making the exhaust port porous. He said that what I thought was carbon was probably rusty metal. this was after many £s worth of spares.
A new cylinder head was almost half much as a new Beta 20, and no guarantee that it would be a fix.
This was at the start of a season, a new engine was quick to install and saved the season.
Another local boat has wasted 2 seasons trying to sort his engine and he still doesn't really trust it.

 

[Kelpie]

Alternatively there was a company selling Chinese marine diesels at well under normal marine prices that got some favourable comments here a year or two back. Don't know if they're still around.

When I looked into these (M Power engines) the savings didn't really stack up until you got in to the larger sizes.

I wonder what the lowest cost electric option is these days. Very limited range but could be viable if you can wait for the right winds. Sailing Uma seem to make it work.

 

[TernVI]

Yes, sounds similar.

I would love to fit a new engine, but we have limited funds and a guy I trust to do the rebuild affordably and cheaply, for less than half the cost of a new engine. He will not rebuild it unless he thinks we will get a decent engine as the end result.

- W

The problem is, it can be quite a few hours work to dismantle an engine fully and really assess how good it will be when 'rebuilt'.
Once you invest that time/cash, you create pressure to carry on.
It will still be an old engine.
In 5 years' time it will be an ancient engine, the value people attach to 'rebuilt' tends to evaporate quite quickly.

Marine Enterprises have a 2GM20F for £2k. I'd be considering that.

 

[Slowboat35]

I'd just add a caveat that you need to read the description of what's been done to 'refurbished' and 'rebuilt' engines found for sale very carefully and apply a healthy degree of scepticism to those over-used descriptions.

Refurbished is likely to mean no more than steam cleaned, blown over with a silver rattle-can and 'successfully run for two hours' on a pallet.
It will look nice and new, but why did the original owner part with it? He didn't do so for fun. Running on a pallet is pretty meaningless, it only shows the damn thing will start. You have no idea what's under the fresh paint.

Rebuilt often turns out to be no more than valves lapped and a new head gasket. That is NOT a rebuilt engine imho. But that's often all that some vendors admit to have done. I've seen these advertised without even the injectors having being cleaned or checked!

Rebuilding Yanmars is horribly costly due to the obscene price of parts. Some pattern parts are available but anything more substantal than piston rings or valve-seals will have to come from Yanmar at £££ if you can even find them. Add anythig like commercial labour costs and it just doesn't stack up.

If you can do it yourself it's well worth a try but be certain of the plan before committting £££ in bits before discovering a stopper... Be prepared to break it for parts before that happens.

Changing like for like is much simpler than changing makes, I've just done a Yanmar to Beta swap and it involved a considerable rework of the beds to fit the new engine - at great expense and beyond my skills. A new Yannie would have worked out cheaper if only for that reason alone.

Sorrry to paint a negative picture but this process is fraught with traps of the unwary or just unlucky.

 

[webcraft]

Marine Enterprises have a 2GM20F for £2k. I'd be considering that.

It's second hand, not rebuilt or reconditioned.

Someone didn't want it.

And anyway, no longer available.


- W

 

[BobnLesley]

...would love to fit a new engine, but we have limited funds and a guy I trust to do the rebuild affordably and cheaply, for less than half the cost of a new engine. He will not rebuild it unless he thinks we will get a decent engine as the end result.

I believe that you're out cruising rather than in home waters, so I'm assuming that the trusted-Engineer is a local professional that you've recently met, rather than someone you've known for years?
As a basic principal, unless you are have the tools and ability to provide 90% of the labour input yourself, it's very difficult to achieve a proper re-build of a small marine diesel engine for less than the cost of its renewal and on more than one occasion on this forum I've warned of the '2 week/200 mile fix' syndrome, for which we cruising yotties are prime targets. Off the top of my head I can recall 8 or 10 people we've met over the years who got their engines overhauled/rebuilt/refurbished somewhere along the way - a variety of engines and locations. The majority of them ended up paying paying far more than had originally been quoted and every single one of them subsequently (6 months to two years) ended up renewing their engine anyway.
I don't know your Engineer or even where you are, but be very careful and make the decision with your eyes wide open.

 

[Davy_S]

Surely the cheapest option would be to whip the head off yourself, check the head gasket,then replace it and run it up and see what happens.

 

[webcraft]

I'd just add a caveat that you need to read the description of what's been done to 'refurbished' and 'rebuilt' engines found for sale very carefully and apply a healthy degree of scepticism to those over-used descriptions.

Refurbished is likely to mean no more than steam cleaned, blown over with a silver rattle-can and 'successfully run for two hours' on a pallet.
It will look nice and new, but why did the original owner part with it? He didn't do so for fun. Running on a pallet is pretty meaningless, it only shows the damn thing will start. You have no idea what's under the fresh paint.

Rebuilt often turns out to be no more than valves lapped and a new head gasket. That is NOT a rebuilt engine imho. But that's often all that some vendors admit to have done. I've seen these advertised without even the injectors having being cleaned or checked!

Rebuilding Yanmars is horribly costly due to the obscene price of parts. Some pattern parts are available but anything more substantal than piston rings or valve-seals will have to come from Yanmar at £££ if you can even find them. Add anythig like commercial labour costs and it just doesn't stack up.

If you can do it yourself it's well worth a try but be certain of the plan before committting £££ in bits before discovering a stopper... Be prepared to break it for parts before that happens.

Changing like for like is much simpler than changing makes, I've just done a Yanmar to Beta swap and it involved a considerable rework of the beds to fit the new engine - at great expense and beyond my skills. A new Yannie would have worked out cheaper if only for that reason alone.

Sorrry to paint a negative picture but this process is fraught with traps of the unwary or just unlucky.

I believe that you're out cruising rather than in home waters, so I'm assuming that the trusted-Engineer is a local professional that you've recently met, rather than someone you've known for years?
As a basic principal, unless you are have the tools and ability to provide 90% of the labour input yourself, it's very difficult to achieve a proper re-build of a small marine diesel engine for less than the cost of its renewal and on more than one occasion on this forum I've warned of the '2 week/200 mile fix' syndrome, for which we cruising yotties are prime targets. Off the top of my head I can recall 8 or 10 people we've met over the years who got their engines overhauled/rebuilt/refurbished somewhere along the way - a variety of engines and locations. The majority of them ended up paying paying far more than had originally been quoted and every single one of them subsequently (6 months to two years) ended up renewing their engine anyway.
I don't know your Engineer or even where you are, but be very careful and make the decision with your eyes wide open.

The engineer is someone a friend has known for years, so it's not a total shot in the dark.

The simple fact is, we cannot afford to re-engine the boat at this point in time.

And new 2GM20s do not exist, so jiggery pokery would be required whatever engine we went for.

If we can get an affordable rebuild that lasts two years we will cross the next bridge when we come to it.

However, no doubt you are all correct and we are doomed to end up rotting somewhere with a broken, engineless boat, the punishment for doing something we cannot afford.

- W

 

[Topcat47]

From you description of the problem there are a number of possible causes. The GM Series motors suffer from exhaust elbow corrosion. This leads to salt water flowing back into the exhaust manifold and the cylinder heads. This frequently results in corrosion between the exhaust valve seats and the waterways in the head. Replacing the head will be prohibitively expensive at Yanmar prices, and you still need to replace the top end gaskets. Before you commit to any expenditure, the heads need to be removed and checked. It is possible to weld up the head around the problem area, the Valve seats will need to be recut and new valves fitted. That assumes there are no other problems with the block and crankshaft. If you're going to all this trouble, then the fuel pumps and injectors should be tested and "repaired" by a professional specialist. It is also possible that you have bent con rods leading to reduced compression. These engines are pretty simple to work on. My last Top end overhaul on my 1GM10 involved new pre-combustion chamber and seals, too. It was half the cost of a new engine and I did all the work myself. Replacing the engine, will at least mean the gearbox and stern gear don't need changing. Re-engining with something else will involve new mountings ( unless you go for a Beta who will match your existing Yanmar mountings ) and probably a new prop. Emulsified lub oil doesn't lubricate well. If you've been running like this, you'll need to be prepared for bottom end problems and you'll be lucky to escape with just a new set of shells. You might have to have the crank re-ground.

It may be cost effective to park up and save for a new plot.