Hand cranking a Yanmar 3Gm30

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Jabamusic

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This query might apply to most (all?) engines, but just in case this one has any peculiar habits I reference it. I was wondering what the proper procedure is to hand crank this engine?
I have found the unused (by me) handle and I thought it might be a good idea to know how to use it!
I know I have to do something with the de-compressors, but which one (s), all of them, one at a time? etc

Any words of advise/cautionary tales of woe?

Cheers all.
 
ctva said:
Are you 6'10", and built like Arnold?

If not, forget it and carry a spare battery.
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I was told that about my old YSB8 but I proved them wrong.

I would suggest it's easier with another pair of hands. First get your starting handle extended so you can get 2 hands on it( Longer length of tube around the handle). Then open all decompressors wind it up as fast as you can while someone holds open the decopressors. when you're ready let the helper release one decopressor, keep winding like billyo as she fires up release the other levers. The lugs on the handle are designed so that it wont take your arm off as she fires up.
Don't forget to turn the ignition on and have the throttle in the usual starting position. If it takes a lot of cranking you may want to think about closing the cooling inlet seacock until she fires up.
 
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I always fancied a spring starter( a proper wind up) . Non electric, non superman solution.

Seriously, what about preheating the air intake with a wee blowlamp, can make a huge difference on a cold mornings winding er over...
 
I think your chances of success are vanishingly small!

Even if you are several times stronger and fitter than me (which you easily could be), the design of most boats seems to give you no way near enough space to get a good rythm going turning it over.
 
maby said:
I think your chances of success are vanishingly small!

Even if you are several times stronger and fitter than me (which you easily could be), the design of most boats seems to give you no way near enough space to get a good rythm going turning it over.
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As an ex boatbuilder I do take exception to that comment...

Have you ever tried fitting an engine, in a yacht??

It's not easy, and we do the best we can...

Let's remember the engines are designed for tractors, not boats...

Please, I would prefer no uninformed comment...

Jon
 
jon711 said:
As an ex boatbuilder I do take exception to that comment...

Have you ever tried fitting an engine, in a yacht??

It's not easy, and we do the best we can...

Let's remember the engines are designed for tractors, not boats...

Please, I would prefer no uninformed comment...

Jon
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Sorry, but I did not intend any particular criticism of boat builders - just a simple statement of fact. Even a fit, strong man will have difficulty hand cranking a medium size marine diesel engine. If it were on a nice solid base in free space with plenty of room to get a good swing going, then it might just be possible. In the confined space (that a boat builder has to work in) of a modern boat, I think it is virtually impossible. I once managed to hand start a little single cylinder 1GM10 - and that nearly killed me. Something three times the size - no way!
 
in the early stages of round the world yacht racing, one big yacht had a starter motor failure. They rigged a spare sheet from a block on the boom directly above the spare engine pulley, and got six foredeck gorillas to run quickly from aft to for'd, holding the sheet which was wrapped round the pulley. It worked.
 
sarabande said:
in the early stages of round the world yacht racing, one big yacht had a starter motor failure. They rigged a spare sheet from a block on the boom directly above the spare engine pulley, and got six foredeck gorillas to run quickly from aft to for'd, holding the sheet which was wrapped round the pulley. It worked.
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I heard of a singlehander doing similar, but with the rope attached to the boom. He gybed all-standing to pull-start the engine.

Pete
 
Niander said:
Id give it a try anyway for the exprience....:)
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I've had a go a couple of times on my 2GM20. Never managed it, although as mentioned by Maby I am constrained by the joinery. The handle bumps against the side of the opening into the engine space; half an inch wider hole and it would have fitted :(

Pete
 
Before trying in earnest give it half a dozen revolutions at a relaxed pace - the engine will then turn more easily.

Single cylinder engines can be harder to start than than those with three cylinders as the bigger ones have more momentum, providing there's a decompression lever for each cylinder.

It's also worth remembering that if your batteries are low, but not totally flat, it's often possible to start a decompressed engine on the starter motor.
 
r_h said:
Before trying in earnest give it half a dozen revolutions at a relaxed pace - the engine will then turn more easily.

Single cylinder engines can be harder to start than than those with three cylinders as the bigger ones have more momentum, providing there's a decompression lever for each cylinder.

It's also worth remembering that if your batteries are low, but not totally flat, it's often possible to start a decompressed engine on the starter motor.
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I'd concur with the above; my ship is old enough to have a handstart firepump(2 cylinder aircooled Lister) and it gets started every week. I have no difficulty with that even though it is mounted awkwardly close to some trunking so I have to stand to one side of the crank. I have certainly found that the 3 cylinder version of the same engine was a snap to get going; once you wound the crank up to speed you could nonchalantly keep it going with one hand while casually flicking the decompression lever over and it would invariably 'tonk---tonk--tonk-tonktonkytonk' away. Single cylinder engines, particularly modern lightweight ones like the GM1, require rather more effort; in order to get a reasonable throttle response out of them the flywheel weight has to be kept down, which is antithetic to ease of handstarting.

The key thing with handstarts is they need to be somewhere about waist height(or at least midthigh) to permit greatest leverage from your arms and legs; the newest engine I've seen with the cranking shaft raised to a useful height(usually with a cased chaindrive bolted to the front of the crankcase) was a Bukh, and that was quite an old one. Do any manufacturers still offer such things? Where the manufacturers bother to include the feature at all these days, it's invariably down around the crankshaft(if not actually the crankshaft itself) making the boatbuilder's task a near impossible one.
 
prv said:
I heard of a singlehander doing similar, but with the rope attached to the boom. He gybed all-standing to pull-start the engine.

Pete
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It would have been fairly exciting if the rope hadn't cleared the pulley and got wound back on. I wonder just how quickly the boom would have disappeared down the companionway. :p
 
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