Yse12 help needed

[DanNewBoatMan]

First time poster and general Boating noob here Daniel.

Got my first sail boat 26ft traker and she has a inboard yse12. I'm having issues she is cranking over but I cant get her to fire. I have diesel primed to the pump and when I tighten up the delivery valve holder I get no diesel out the other end of the high pressure line. I dont know if the pump is producing enough pressure or if I've upset the regulator to the point where it's not working but I'm stumped is anyone able to help me through this I'm desperate. Shes set to go back in the water next week.
Thanks in advance. I really appreciate any and all help. Cheers!

 

[earlybird]

Are you sure you have bled every scrap of air from the high-pressure pipe between the injection pump and the injector? Loosen the pipe connector to the injector and crank the engine over, with the decompressor lifted, until fuel flows freely from that connection. Do this with the speed control lever at maximum. Then tighten the pipe connection.

 

[CJU]

We had a YSE12 on our old boat and had the same problem When we bought her she was ashore and had been a bit neglected.
I found, after a lot of trial and error, that the rings were stuck in their grooves and the valves werent sealing. This all caused lack of compression, so no firing.
If you can borrow the equipment a compression test would show up the lack compression.
To find whether he injector is opening you should hear an audible click when it does open. Ours didn’t because the injector pump had some internal corrosion. We had the injector and pump overhauled and they were then fine.
I took the head to a local HGV workshop and they put a new valve seat and refaced the valves and seats.
The YSE is a horizontal single so you can do a lot of things without taking the engine out, including taking out the piston.
I managed to free the rings by heating the piston in an oven and gently tapping them all round.
After all that the engine performed very well for the next 10yrs but it was noisy and did vibrate, as you might expect.
I think the manuals are available on line, if you need them.

 

[rowlock]

From your post it is not clear that the following is relavent however in the interest of trying the simple stuff first:
The "throttle lever/engine speed control is also the fuel shut off, ie stop control. Advance the throttle lever to full speed position and then attempt to bead the system. If fuel is present at the injector and there is a hint of compression try a start but note it is always necessary to provide some throttle, full, is best from cold as with the lever set against the minimum speed stop fuel is cut off.

 

[vyv_cox]

A further point on compression if fuel turns out not to be the problem. The cylinder head bolts on this engine have very coarse threads. Mine loosened themselves during a fairly long passage under engine, which then would not restart.

 

[DanNewBoatMan]

Are you sure you have bled every scrap of air from the high-pressure pipe between the injection pump and the injector? Loosen the pipe connector to the injector and crank the engine over, with the decompressor lifted, until fuel flows freely from that connection. Do this with the speed control lever at maximum. Then tighten the pipe connection.

I think I may have cocked this step up i made sure i had diesel coming from the pump past the nrv setup then I tightened the delivery valve setup. After this I installed the high pressure line. Seems I may have to connect the line first and before tightening the delivery valve setup verify inhale diesel coming through. Will try this tomorrow and give some feedback.

 

[DanNewBoatMan]

I appreciate the replies thanks guys. I have no doubt it will fire up once I can get fuel through to the injector end of the high pressure pipe. Will keep you chaps informed.

 

[DanNewBoatMan]

Bit of an update, my mate came round and has extensive knowledge and says my motor is healthy but is leaking compression through the intake valve not seating properly so I'm gona have to pull the head and reseat the valve. I'll do it myself with some grinding paste. Hopefully this does the trick.

 

[garymalmgren]

Hello Dan
I have pretty extensive experience with the early Yanmar YS models.
They are noisy lumps, but extremely tough and simple engines.
I think you can't go wrong with doing the valves.
An oil change and removal of the oil filter for a clean and check (metal particles) is also a good idea.

Lastly, my engine had exactly the same symptoms as you and it came on suddenly.
On the net I found a site that recommended readjusting the fuel pump delivery needle.
Did that and she fired up first time and hasn't missed a beat since then.

The instructions in the manual were a little confusing so I have simplified them and will attach.
Come back with the results please, I enjoy learning how others tackle problems.
Gary

 

[DanNewBoatMan]

Hello Dan
I have pretty extensive experience with the early Yanmar YS models.
They are noisy lumps, but extremely tough and simple engines.
I think you can't go wrong with doing the valves.
An oil change and removal of the oil filter for a clean and check (metal particles) is also a good idea.

Lastly, my engine had exactly the same symptoms as you and it came on suddenly.
On the net I found a site that recommended readjusting the fuel pump delivery needle.
Did that and she fired up first time and hasn't missed a beat since then.

The instructions in the manual were a little confusing so I have simplified them and will attach.
Come back with the results please, I enjoy learning how others tackle problems.
Gary

Thanks Gary, you dont happen to live near silverdale do you?

 

[garymalmgren]

Not even close Dan. I live in Sendai on the Pacific coast of Japan.
Gary