Yanmar YSE8 manual cranking

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Stonemonkey

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Today my old engine failed to start using the electric starter. Since I have never tried to start the engine manually I thought it would be good to know how to do it till I figure out which of the involved electrical parts (solenoid, starter, wires etc) are broken. I found some old pieces of a manual where the procedure is described and tried to follow. I skipped adjusting the decompressor because of the rust and got stucked trying to rotate the handle. It goes easy for half of the turn then it becomes super hard to turn it. No way I can perform a complete rotation. The other way around (clockwise) is skipping like a back bike weel does when pedaling backwards. I checked on YouTube and found couple of videos where the authors are manually cranking it super easy. I'm definitively missing something very important. I would appreciate if someone with experience, in how this kind of engine works, could share some thoughts of what am I facing here. Thank you in advance.
 
A diesel engine has a very high compression ratio. IIRC it is Boyles law that ignites the fuel. Compress gas enough and the tempreture rises enough to start it burning. One in good condition WILL be hard to turn past the compession stroke.

If you wish to crank it with the handle you must free off the stuck decompression lever.

A diesel engine has, compared to a petrol engine, a really high compression ratio. Turning one in good condition over compression without using the compression release is really hard.

Fix the stuck decompression lever. Turn on the ignition, insert starting handle. Set throttle to your prefered starting position. Operate the decompression lever and hold it open. With the other hand wind the starting handle as fast as you can. When you are unable to note any increase in speed release the decompressor lever - but keep winding!

The engine should now start.

If not, check fuel supply.

Sometimes getting a helper to operate the starter moror as you are winding with the handle gives that bit extra. One of Tom Cunliffe's tricks.

Go for it - I often started our early single cylinder Yanmar that way to save the battery. The charging was by dynostart and was not very good.......................
 
Stonemonkey said:
Today my old engine failed to start using the electric starter. Since I have never tried to start the engine manually I thought it would be good to know how to do it till I figure out which of the involved electrical parts (solenoid, starter, wires etc) are broken. I found some old pieces of a manual where the procedure is described and tried to follow. I skipped adjusting the decompressor because of the rust and got stucked trying to rotate the handle. It goes easy for half of the turn then it becomes super hard to turn it. No way I can perform a complete rotation. The other way around (clockwise) is skipping like a back bike weel does when pedaling backwards. I checked on YouTube and found couple of videos where the authors are manually cranking it super easy. I'm definitively missing something very important. I would appreciate if someone with experience, in how this kind of engine works, could share some thoughts of what am I facing here. Thank you in advance.
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Welcome to the forums!

As rotrax said, using the decompression lever is essential if you're going to have even a chance of manually starting your engine. One of my early boats had a smallish Volvo engine with a starting handle, and I tried manually starting it out of curiosity. Even using the decompression lever, I couldn't do it! People say that in an emergency the adrenaline kicks in and we develop superhuman strength; it would certainly be needed!

So sort out the electrical starting system first.
 
YSE's can't kick back. The "back bike wheel" refered to by the OP is just that. A ratchet wheel in the chain drive system. With it's heavy flywheel and well positioned starting handle on top of the engine, a YSE is one of the better engines for starting. A working decompressor is essential though. A tin of spinach also helps.
 
Agree decompression lever must work or it will not start. When I had a YSE I used to start it single handed. I devised a rope from the lever and led it back to the front of the engine , then pulled the rope until the lever opened and then stood on the rope. Then wind the handle as others have said and then take your foot off the rope. and keep turning. Always worked for me.
 
After I applied some WD40 on the decompression lever axe and spring, it unlocked nicely and I could rotate it. The engine was still opposing a lot of resistance when I was leaving the decompression lever to go back to its initial position even after 6-7 rotations having a lot of momentum in the flywheel. I almost gave up. I started to check again the electric connections and wires, I figured out that one of the connector (the thin wire) on the solenoid was very rusted. I replaced it and the starter begun to click when engaging the key, but without spinning the engine. As suggested by someone on a forum I hit the starter couple of times with a hammer and suddenly it started to work. After turning the engine on/off couple of times with the battery, I just wanted to try one more time to crank it manually and surprisingly it started super easy. Repeating the operation gave me a lot of satisfaction, cause I'm now able to crank it both ways. Still can't explain why it wasn't working after freeing the decompression lever. Thanks for all your thoughts. Nice to see people care and take the time to respond to beginners like me.
 
davidmh said:
Agree decompression lever must work or it will not start. When I had a YSE I used to start it single handed. I devised a rope from the lever and led it back to the front of the engine , then pulled the rope until the lever opened and then stood on the rope. Then wind the handle as others have said and then take your foot off the rope. and keep turning. Always worked for me.
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That is a good tip and the way I used to hand start my Yanmar 15hp twin engine-with a great deal of effort and some starter spray..
 
We had a similar engine in a canal narrowboat in the 70's.

I always hand cranked it first start of the day.

Ours had a dynostart - the dynamo also served as the starter motor.

When using the dynostart the decompressor was always used so it rotated faster.

Glad you have sussed it, well done.
 
Sorry to resurrect this thread, but I need some advice regarding my hand cranking gears. It’s freewheeling all the time, ie, it just spins on its own and doesn’t turn the engine over. Any ideas where I should start looking to make it engage and work properly?
 
If it turns freely both ways it is the ratchet gone in the freewheel. However, one engine-cant recall the make-had a dog clutch that needed to be engaged for hand cranking. It popped out when it started. Check if yours has this and try engaging it.
 
The sprocket (14-30) turned by the starting handle+chain engages with the drive ring (14-31) courtesy of 2 steel balls (14-33).
14-30 should freewheel when turned clockwise and engage when turned anti-clockwise.
Perhaps the steel balls are stuck (it can get a bit oily around there, in fact there's an arrow on the casing directing you to oil the sprocket) so perhaps you can get a lubricant spray in there to clean things up.
Or the steel balls could have been left out at some stage in the engine's life I suppose..

yse.JPG
 
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