Yanmar YSE 8 crank chain doesn't stop

[Smyg]

Hello everyone and thanks in advance!,
This is my query:
My Yanmar YSE 8 starts but the crank chain also turns all the time with the crankshaft. It started to do this more and more often so I have tightened the stopper (screw with "L" shape") but nothing, it keeps turning and making a very ugly noise and it is braking the engine. Is there anyone who know how to solve this problem?. Thank you so much!.
Best regards,

 

[earlybird]

Long time since i had a YSE8, but doesn't the lower sprocket engage / disengage from the starting shaft via a dog clutch? This may be seized.

 

[CaptainHornbag]

I've got a similar YSB12. Never had this problem but I'm wondering if the sprocket hasn't been lubricated sufficiently and the bearing seized? Behind the sprocket is an oil hole which should receive a few drops of oil before each operation. Maybe give this bearing a flush with WD40 to see if it frees up. Otherwise this bearing might need to be replaced. I would run the engine again until this has been fixed.

 

[Smyg]

Hi Earlybird, thanks a lot for your reply. That is exactly what happens, either the top or bottom sprocket does not disengage and it spins constantly (I think It is the bottom one). My engine is a bit different as it has the top sprocket larger and that is where the crank is operated from (starting shaft).
How can it be seized?. Thanks so much.

 

[Smyg]

 

[garymalmgren]

Behind the bottom sprocket there is a housing (14-31. )
In this housing there are three balls (14-35 I think)
When you rotate the starting handle the balls centrifugally throw out and engage.
If you lock the upper shaft with the locking screw (14-5) the balls should disengage and the whole unit will not rotate.
If dirt or gunk gets in there, the balls sometimes don't disengage, Even one ball will keep the shaft rotating.

As Cptn Hornbag has suggested, Spay some WD 40 in behind the lower sprocket to wash out the dirt, add a few drops of oil and use the locking screw and you should be back in business.

gary

 

[Smyg]

Thank you very much for your answer CaptainHornbag and garymalmgren. I will try that and inform you how it does.
Best regards to all of you.

 

[Smyg]

Hi, I did exactly what you said, I have sprayed W40 and It worked, even without tightening the stopper screw. Thanks so much to all.