Yanmar YSB12 - Advice needed

[djyacht]

I`ve posted previously about starting problem on my newly acquired boat. Despite long cranking etc could not get it to run. I also realise that I may now have water ingression into the cylinder (there was certainly a sloshing sound.)
Three weeks ago I removed the injector pump and injector and had them professionallly stripped, cleaned and tested.The engine at that point would turn over manually with the starting handle.

Today I went to the boat and found that the engine seem to be locked solid and I cannot get any movement with the handle. (I also don`t seem to be able to rotate the output shaft). I did not refit the injector pump or injector.

I have started to strip off the cylinder head, with the thinking that water in the bore may have seized the piston, although three weeks since last movement makes this seem unlikely, and I`m puzzled by lack of movement at the output.
I`ve read previous posts about seized pistons but would be grateful for any advice.

Thanks

David

 

[sailorman]

dont forget to replace the washer between the head & the injector, they are a "once use" item.
i would try more muscle on the handle / flywheel before stripping the head
did you inject engine oil into the intake manifold,( there is a lift up cap as on a bicycle) before you started cranking

I`ve posted previously about starting problem on my newly acquired boat. Despite long cranking etc could not get it to run. I also realise that I may now have water ingression into the cylinder (there was certainly a sloshing sound.)
Three weeks ago I removed the injector pump and injector and had them professionallly stripped, cleaned and tested.The engine at that point would turn over manually with the starting handle.

Today I went to the boat and found that the engine seem to be locked solid and I cannot get any movement with the handle. (I also don`t seem to be able to rotate the output shaft). I did not refit the injector pump or injector.

I have started to strip off the cylinder head, with the thinking that water in the bore may have seized the piston, although three weeks since last movement makes this seem unlikely, and I`m puzzled by lack of movement at the output.
I`ve read previous posts about seized pistons but would be grateful for any advice.

Thanks

David

 

[ghostlymoron]

I've no knowledge of your particular engine but it sounds like you have sucked some seawater into the cylinder by extended cranking. It's advisable to close the inlet seacock if cranking for more than a few seconds. Seawater will corrode very quickly and could explain the lack of movement. I think removing the head and having a look is a good plan especially if you can hear water within. If it's seized you may be lucky and be able to free it by putting some penetrating oil in and allowing to seep through before trying to turn the engine over again.
You should be able to turn the prop shaft with the engine in neutral.
Good luck

 

[sailorman]

with the injector removed the engine should just spin over

I've no knowledge of your particular engine but it sounds like you have sucked some seawater into the cylinder by extended cranking. It's advisable to close the inlet seacock if cranking for more than a few seconds. Seawater will corrode very quickly and could explain the lack of movement. I think removing the head and having a look is a good plan especially if you can hear water within. If it's seized you may be lucky and be able to free it by putting some penetrating oil in and allowing to seep through before trying to turn the engine over again.
You should be able to turn the prop shaft with the engine in neutral.
Good luck

 

[NickRobinson]

Hi
Sorry to hear about your engine woes.
It does sound like a seized piston/rings issue. (Unlikely to be anything else if completely stuck, not just unable to turn 360 degrees)
BTW, not sure about your skills so apologies for the next bit. Removing the injection pump rather than lift or filter block, means you may have difficulty sorting out the shims etc. on replacement. Sorry...

Wellie-ing the crank with thin oil like diesel injected down the cylinder should work, do not turn crank one way, you may break rings. 'Wiggle' it forward and back, when it starts to move, you should increase the degrees turned incrementally until you get complete revs.

Once it starts, get it really hot 'n bothered (run under load) as the rings will need freeing off from the piston grooves.

Let us know

Nick

 

[djyacht]

Thanks for advice so far, which is appreciated. - I`ll be back over there tomorrow so will follow up.. I retained the shims before the pump was serviced and tested, but may need to reshim if timing is out. I have been trying to turn the engine on the starter handle system, which will only allow cranking one way- access to the crankshaft end is difficult (the boat is an IP24.

Any further observations very welcome


David

 

[sailorman]

i dumped my hand start, never needed it

Thanks for advice so far, which is appreciated. - I`ll be back over there tomorrow so will follow up.. I retained the shims before the pump was serviced and tested, but may need to reshim if timing is out. I have been trying to turn the engine on the starter handle system, which will only allow cranking one way- access to the crankshaft end is difficult (the boat is an IP24.

Any further observations very welcome


David

 

[NickRobinson]

I have been trying to turn the engine on the starter handle system, which will only allow cranking one way- access to the crankshaft end is difficult (the boat is an IP24.

David

Can you get easy access to the starter? Remove it and you can use a large blunt screwdriver to lever against the ring gear.

You could hand starter it one way then lever it back the other..

(If it had been a Mk 1 Cortina I'd have said put it in fourth and rock it back and forward...!)

N

 

[sailorman]

http://www.howtomendit.com/answers.php?id=87217

 

[Topcat47]

If the engine was turning easily three weeks ago, it's unlikely to have seized up from corrosion, I think there's probably still water in the cylinder. Beware of the dreaded hydraulic lock. Water is incompressible and trying to start the engine if there is water in the cylinder will cause damage. If you're unlucky it might be a cracked block as well as a bent con-rod and/or broken piston.

It'd be safer to remove the injector. If the engine cannot be turned over with the injector removed, there may be other causes but I've shifted pistons in corroded bores by judicious use of penetrating oil and muscle power. PM Vyv Cox he's a mine of useful information on this.

 

[sailorman]

If the engine was turning easily three weeks ago, it's unlikely to have seized up from corrosion, I think there's probably still water in the cylinder. Beware of the dreaded hydraulic lock. Water is incompressible and trying to start the engine if there is water in the cylinder will cause damage. If you're unlucky it might be a cracked block as well as a bent con-rod and/or broken piston.

It'd be safer to remove the injector. If the engine cannot be turned over with the injector removed, there may be other causes but I've shifted pistons in corroded bores by judicious use of penetrating oil and muscle power. PM Vyv Cox he's a mine of useful information on this.

The injector is out for service. therefore nothing to compress

 

[Topcat47]

Can you turn the engine backwards at all? I don't have the manual for your engine, but the 1Gm10 has a pre-combusion chamber with small holes to the cylinder. If the pre-combustion chamber is still in place, and in my engine it was fairly well jammed in, you may still have difficulty turning it over the right way, if there's water in the cylinder. It will suck air in reverse if the valves are closed.

 

[sailorman]

I say for the 3rd time
the injector has been removed = No compression

Can you turn the engine backwards at all? I don't have the manual for your engine, but the 1Gm10 has a pre-combusion chamber with small holes to the cylinder. If the pre-combustion chamber is still in place, and in my engine it was fairly well jammed in, you may still have difficulty turning it over the right way, if there's water in the cylinder. It will suck air in reverse if the valves are closed.

 

[Topcat47]

Ok, I heard you. IF you have a hydraulic lock AND a pre-combustion chamber, the water in the cylinder will not free flow out of the injector fitting. The Pre-combustion chamber holes into the cylinder are too narrow. Even if there was gas in the cylinder, you'd find it difficult to force it through these holes by hand. It's analogous to getting the air out of the vents in a rubber dinghy, the "hole" is too small to allow all the air out at once. It's not like removing a spark plug from a petrol engine.

If you have no liquid in the cylinder and no pre-combustion chamber (or if the pre-combustion chamber has also been removed) it will be easier to turn the engine over by hand.

 

[SteveTibbetts]

Can you get easy access to the starter? Remove it and you can use a large blunt screwdriver to lever against the ring gear.

You could hand starter it one way then lever it back the other..

(If it had been a Mk 1 Cortina I'd have said put it in fourth and rock it back and forward...!)

N

I did the screwdriver in the ring gear thing with my yse8 when I had the same problem. End of the driver broke off so I had to separate the gearbox to retrieve it.


Sorry, can't remember why the engine wasn't turning over but I think it might have been just trying to turn against the compression.

Steve

 

[djyacht]

Update.

Removed the head and as suspected it was quite full of water (seawater) from all of the cranking, and rust has formed. I`ve dried it all off and applied loads of WD40 which I`ll leave soaking over the weekend and then soak it again on Monday. I`m not going to attempt cranking the engine on the manual staring handle until I`m confident that the WD40 has soaked through.

I`ll post some pcs if anyone is interested.

 

[djyacht]

Yanmar YSB12 Advice needed- UPDATE

Update.

Removed the head and as suspected it was quite full of water (seawater) from all of the cranking, and rust has formed. I`ve dried it all off and applied loads of WD40 which I`ll leave soaking over the weekend and then soak it again on Monday. I`m not going to attempt cranking the engine on the manual staring handle until I`m confident that the WD40 has soaked through.

I`ll post some pcs if anyone is interested.

Following this I then soaked with Plusgas for two days, One of the challenges is that with the cylinder being horizintal it`s not possible to simply fill it and then leave it. I used some Blue Tak at the top of the cylinder to creat a little dam, which helped, and then switched to ACF-50, which foams at first and stays in place. Today I cut a disc out of 12mm ply to fit in the cylinder and pushed into to the bore to make contact with the piston. I then gave the disc a couple of mild taps with a mallet before then fitting a spanner to the crankshaft end nut. I then tapped this carefully in the direction that would pull the piston down the bore.

SUCCESS! I finally got the movement needed and drew the piston further down the bore. I`ve now left it soaking with ACF-50 and will then commence further movement and cleaning of the bore, before refitting cylinder head etc. One more step along the road......

Thanks aagin for all the advice given - I really appreciated folks taking the time and trouble to respond.


David

 

[sailorman]

Thats all good.
on mine i made up a high rise exhaust manifold to avoid that very problem

Following this I then soaked with Plusgas for two days, One of the challenges is that with the cylinder being horizintal it`s not possible to simply fill it and then leave it. I used some Blue Tak at the top of the cylinder to creat a little dam, which helped, and then switched to ACF-50, which foams at first and stays in place. Today I cut a disc out of 12mm ply to fit in the cylinder and pushed into to the bore to make contact with the piston. I then gave the disc a couple of mild taps with a mallet before then fitting a spanner to the crankshaft end nut. I then tapped this carefully in the direction that would pull the piston down the bore.

SUCCESS! I finally got the movement needed and drew the piston further down the bore. I`ve now left it soaking with ACF-50 and will then commence further movement and cleaning of the bore, before refitting cylinder head etc. One more step along the road......

Thanks aagin for all the advice given - I really appreciated folks taking the time and trouble to respond.


David

 

[djyacht]

Yanmar YSB 12 advice - SUCCESS

Got the engine running again - main challenge after freeing it off was bleeding the injection pump. I`d misunderstood the arrngements for this, but after a bit of thinking and double checking succeeded. The main challenge was the manual cranking of the engine, which is difficult because access with starting handle is restricted by cabin arrangement, so only half a turn possible at a time.

Thanks again to all.


David