Hi From Down Under

[Compass790]

If you find the exhaust elbow is knackered you can make one like this.
It needs to be wrapped up to water injection point. This was just stick welded with 2.5mm 316LC rods. Would be nicer TIG welded but was what was availiable.
Note: the water injection is on the downhill side of exhaust so it wont go into head. Of course it is not cool on the bend like Yanmars thats why it needs exhaust wrap.

[Gregted]

Originally Posted by nofacey

Too many identified items (sludge, disconnected water, not turning over even manually) that I’d stop trying to “start” the engine and just tear it down - small enough you can likely do this in place.

I think you are spot on. It really needs a tear down and then we'll know where we stand. Too many unknown causes/problems to be a reliable motor.



The previous owner wasn't too concerned but I would like the inboard to be the primary propulsion. Apart from free wind power, of course.

[Gregted]

Originally Posted by Compass790

If you find the exhaust elbow is knackered you can make one like this.
It needs to be wrapped up to water injection point. This was just stick welded with 2.5mm 316LC rods. Would be nicer TIG welded but was what was availiable.
Note: the water injection is on the downhill side of exhaust so it wont go into head. Of course it is not cool on the bend like Yanmars thats why it needs exhaust wrap.

That looks doable. Why does it need to be wrapped and with what?


Is the wrap to insulate (separate cabin) from the hot exhaust water or hot exhaust gasses which wouldn't make much sense as the whole motor would be hot under power.



I see no evidence of wrapping on the original exhaust. Wouldn't everything from the block to the mixing elbow be hot anyway or is it just the exit from the hull that needs to be cooled which would be achieved by the water at the elbow.


So many questions but luckily, so many helpers.

[Fore and Aft]

Gregted here is another Yanmar 12 closer to you that could be good for parts or a replacement engine. I wonder what model it is?
Cheers

[Gregted]

Originally Posted by Fore and Aft

Gregted here is another Yanmar 12 closer to you that could be good for parts or a replacement engine. I wonder what model it is?
Cheers

That's a wicked collection of home made mods there. The chain driven crank and welded fuel tank looks very functional.


Not sure if it is the same model but thanks for the link anyway. We're hoping most of our engine is usable.


I just found a seller on evilbay who has a piston rebuilt kit with liner and gaskets and o-rings for $480 delivered so we might get out of this rebuild reasonably cheaply..

[RaymondR]

I spent a couple of weeks in the Boyne River last year on my way to Cairns, lovely place Tannum Sands and the bike tracks in the area are great. It's now on my list as one of my regular stops.

I'd be inclined to take it out of the boat and pull it right down on the bench for a complete overhaul, those old engines can be surprisingly cheap to rebuild and you would have more confidence in it then.

[Wotname]

Originally Posted by Gregted

That's a wicked collection of home made mods there. The chain driven crank and welded fuel tank looks very functional.


Not sure if it is the same model but thanks for the link anyway. We're hoping most of our engine is usable.


.......

You may be surprised to know the chain driven crank shown is an original Yanmar option! It was designed to be able to hand crank the engine from the front or the rear.

There was an option for engine mounted fuel tank but the one shown was definitely not Yanmar .

For future reference, the principle differences between the Yxx models are -
YSE - Deckel type injection pump and cast iron gearbox housing
YSB - Deckel type injection pump and alloy gearbox housing
YSM - Bosch type injection pump and alloy gearbox housing

The two problem areas money wise will be if the crank main bearing at the flywheel end is worn beyond limits and if the oil pump rotor housing is worn.

There is a good chance the crank bearing will be OK but if not, it is expensive!!
The other bearings are reasonably priced and oil seals etc are off the shelf commercial items that are available at any bearing shop.

The oil pump rotor housing is often worn on high hour engines and while it is not replaceable, it is repairable if you can find a good machinist.

But let's not cross those bridges unless they present themselves.

Just for fun, here is a picture of an original Y series engine mounted fuel tank. Note the fuel 'gauge'. The fuel filter internal behind the fuel cock.

[Gregted]

Originally Posted by RaymondR

I spent a couple of weeks in the Boyne River last year on my way to Cairns, lovely place Tannum Sands and the bike tracks in the area are great. It's now on my list as one of my regular stops.

I'd be inclined to take it out of the boat and pull it right down on the bench for a complete overhaul, those old engines can be surprisingly cheap to rebuild and you would have more confidence in it then.

I think that will be the final plan. A complete pull down and rebuild on the bench.


We love it here too. Moved up here 8 years ago from Frigid Toowoomba after 50 years of cold winters, and never want to see another frost as long as I live. This climate is perfect. A bit humid but a sea breeze most days.

Originally Posted by Wotname

You may be surprised to know the chain driven crank shown is an original Yanmar option! It was designed to be able to hand crank the engine from the front or the rear.

There was an option for engine mounted fuel tank but the one shown was definitely not Yanmar .

For future reference, the principle differences between the Yxx models are -
YSE - Deckel type injection pump and cast iron gearbox housing
YSB - Deckel type injection pump and alloy gearbox housing
YSM - Bosch type injection pump and alloy gearbox housing

The two problem areas money wise will be if the crank main bearing at the flywheel end is worn beyond limits and if the oil pump rotor housing is worn.

There is a good chance the crank bearing will be OK but if not, it is expensive!!
The other bearings are reasonably priced and oil seals etc are off the shelf commercial items that are available at any bearing shop.

The oil pump rotor housing is often worn on high hour engines and while it is not replaceable, it is repairable if you can find a good machinist.

But let's not cross those bridges unless they present themselves.

Just for fun, here is a picture of an original Y series engine mounted fuel tank. Note the fuel 'gauge'. The fuel filter internal behind the fuel cock.

Found a Yanmar Trochoidal oil pump rotor set on evilbay for $220 ish delivered from UK but I assume that the housing in the crankcase is the part that you are talking about.

[MicHughV]

In my neck of the woods there are diesel engine "schools" where youngsters can learn the fine art of disassembling a diesel engine and rebuilding it. Most often the " rebuilds" are some or other diesel engine that has been yanked out of a boat. These are typically " not for profit" educational facilities geared towards misspent youth. These facilities have the tools and other equipment to tackle most anything. I know of several sailors having taken their misbehaving diesel engines there.

It might be worth to check around and see if anything like that is in your area.

[Compass790]

Originally Posted by Gregted

That looks doable. Why does it need to be wrapped and with what?


Is the wrap to insulate (separate cabin) from the hot exhaust water or hot exhaust gasses which wouldn't make much sense as the whole motor would be hot under power.



I see no evidence of wrapping on the original exhaust. Wouldn't everything from the block to the mixing elbow be hot anyway or is it just the exit from the hull that needs to be cooled which would be achieved by the water at the elbow.


So many questions but luckily, so many helpers.

Well cobber it depends how hot you want it inside your boat & if you want to be spared the pain of touching a hot exhaust.


Yes no wrapping on original exhaust but at the elbow it is cool as water surrounds it. Engine doesnt get above about 60oC during operation as its raw water cooled but exhaust gas temp may be 500oC so my exhaust build type is that hot up to the point of water injection. The water injection is necessary to not melt the plastic muffler & keep the inside of boat cooler. The ss pipe holds the heat for a long time too. Dont ask me how I know

You can use kaowool or just fibreglass cloth tape to wrap it.It would actually be better for longevity if not wrapped but up to you how much heat you want inside.
I wouldnt order a oil pump rotor assembly until you find out wether its within tolerances as Wottie said. You need to read the service manual re checking oil pump tolerances first. You can get much cheaper aftermarket ones than that.
Find out what is faulty for a start.

Good choice IME rebuilding it rather than relying on outboard

[Gregted]

Yea. Definitely don't want it any hotter in that cabin than it has to be. Worked up a fair sweat the other day just checking the injector and other repairs.

That would also explain why the seat above the motor in the galley was so heavy and thick. A hot seat might be great in the colder climes but not an asset on the Capricorn Coast.

The cabin has reasonable cross flow ventilation under way but I will def look for some Kaowool or similar.

We are heading out to the yacht this Saturday so might take the head off and see where we go from there. I did see the oil pump tolerances in the manual so that will also be something to check before we start our around the world trip..

[Gregted]

Originally Posted by MicHughV

In my neck of the woods there are diesel engine "schools" where youngsters can learn the fine art of disassembling a diesel engine and rebuilding it. Most often the " rebuilds" are some or other diesel engine that has been yanked out of a boat. These are typically " not for profit" educational facilities geared towards misspent youth. These facilities have the tools and other equipment to tackle most anything. I know of several sailors having taken their misbehaving diesel engines there.

It might be worth to check around and see if anything like that is in your area.

Will check that option out if machining is needed. The piston liner and piston should be a simple enough replacement. The exhaust elbow also looks doable but won't know anymore until we get it turning over, I guess then we'll see how the dollars and stress add up..

[Compass790]

gregted i imagine supercheap auto has exhaust bandage when it comes to that. you have a lot to do before that point. the liner can be a mission to remove, check threads on that for tips. no time to post more atm. good luck.

[Gregted]

Originally Posted by Compass790

gregted i imagine supercheap auto has exhaust bandage when it comes to that. you have a lot to do before that point. the liner can be a mission to remove, check threads on that for tips. no time to post more atm. good luck.

I'll look for some insulation when we actually get it running.


Also found some pics of cylinder removal tools. Prices range from next to nothing homemade, to over $2000.

[Wotname]

DIY is easy with normal tools (angle grinder & drill).

I'll find a recent link later when I get a moment.