Starting a small diesel, manually...just how hard can it be?

[ghostlymoron]

Hey, I don't like the reference to the past tense! I still have a Dynastart.

The Dynastart wasn't a coiled spring, it was a combined dynamo and electrical starter motor.

 

[sailorman]

It wasnt very good as a starter motor or a dynamo

 

[ghostlymoron]

As far as I know, the Beast is still ticking along merrily.

The real answer is you just don't know. You may be lucky as Dylan seems to have been with the engine in his Centaur, or unlucky as he was with the slug. There will always be the risk that a repair/replacement bill of a diesel in a small old boat will be more than the boat is worth.

 

[AngusMcDoon]

As far as I know, the Beast is still ticking along merrily.

I believe so too, but Dyl did have a few problems.

 

[Uricanejack]

One of the things I find quite disappointing about my boat is the lack of a hand crank for my Yanmar 3GMF.
I started a thread just after I bought the boat about the possibility of fitting a hand crank as an aftermarket option.
I took the forum advice and gave up on this idea as impractical and bought one of those little portable starter kits.
I think I started one nice ladies car for her in a parking lot once, less than 2 years and it wont hold a charge.
The one time I needed it. It was dead.( I had left my car parked for two weeks while sailing).

I don’t like the idea of being with out a back up.
I used to regularly hand start small diesels, sail boats were often difficult due to awkward positions. And on some the inability to turn the handle due to interference.

As a boy I used to hand crank a 6 cylinder Kelvin(I think it was a straight 6 rather than 8) I was 11 about 4ft 8 and not very heavy.
There was two of us, my friend the same age.
She would do the compression leavers and throttle. (her dad was the skipper)
She would open all the leavers. Set the throttle
I would turn slowly at first gradually getting up to speed.
When going as fast as I could I’d nod my head and she closed the first cylinder. It would fire usually first time.
Once running leavers were closed on at a time
I often got sprayed by bilge water from the fly wheel if I hand pumped out enough.

My 24ft'r had an outboard on a bracket, a mid 80's Honda, worked every time.

 

[Avocet]

Camshaft half engine speed surely? It must put some strain on the cam belt/chain/gears as well.

No, it really is 1/4! I found out the hard way when I put an external alternator on it (the original being a really rubbish one built into the flywheel). Closer inspection revealed 2 cam lobes per valve - one each side of the cam, 180 degrees opposite each other. The cam is gear-driven and has survived 25 years use (and two immersions). I don't suppose they expected it to b hand started that much (ours never has because of the installation position) but they're marinised versions of small plant engines, so I imagine they get hand-started fairly often.

 

[AngusMcDoon]

No, it really is 1/4! I found out the hard way when I put an external alternator on it (the original being a really rubbish one built into the flywheel). Closer inspection revealed 2 cam lobes per valve - one each side of the cam, 180 degrees opposite each other.

That would explain it. I wonder what the advantages of that design are.

 

[PuffTheMagicDragon]

The first 'dinghy-with-a-lid' that I had was a 20 foot Vivacity. I tried a long shaft outboard on a bracket for a couple of seasons. It was OK for going in and out of harbour but hopeless when there were waves; the prop would either be buried under two feet of water or else it would be churning foam at the surface. I did consider making a well and thought hard about how to go about it.

Eventually I decided to go for a 'proper' inboard. I fitted a new single-cylinder Lombardini Marine diesel under the companionway (perfect snug fit) and cut a slot for a shaft tunnel (home made) and fitted a P-bracket. That little engine gave me 6 hours per gallon at trolling speed. The difference in handling from when I had the outboard was like comparing 'rain with dew', if I am permitted to translate a local saying into English..

Some people do not bother with water-cooled and fit the agricultural equivalent which is air-cooled (and cheaper). Given your climate this might not be a bad idea if you can arrange for adequate cold-air ventilation.

Just something for you to think about.

 

[2Tizwoz]

The Lister and Petter diesels had robust drive to their camshafts so that they could be used to supply power at half engine speed which was convenient for many industrial uses and the starting handle was usually on the camshaft also so a good amount of momentum could be created for starting by hand before closing the decompression lever.

An even faster gearing would make hand starting still easier. That's aside from any industrial use.

To make hand starting as easy as possible the Lister and Petter engines and many others have a means of increasing the fuel supply for starting and a lever for priming the injector and putting some additional fuel into the cylinder. The smaller Petter engines also had a means of injecting oil into the cylinder to increase compression for easier starting.

Injectors in good condition producing a fine mist of fuel make starting easiest also.

I do like to being able to start my old MD7B by hand when the batteries have too little left in them.

 

[Noahsdad]

Got a 3GMD with a starting handle and decompressors.
Two turns of the handle to one engine revolution.
Only ever used the handle for setting the tappets!
When I'm feeling brave I will have a crack at starting with the handle! Maybe.

 

[ripvan1]

And good luck with the Petter :encouragement:

Well the previous AC2W which has now been fixed and is in a fishingboat lasted for yonks so hoping this one will see me good for a few years.

It was easier to take the original out and sell for fixing and buy the newer less used one with another almost complete engine in bits, than try to fix it in situ. Everyone's happy

 

[Avocet]

That would explain it. I wonder what the advantages of that design are.

The only advantage (as far as I can see) is the 4 : 1 speed advantage when hand cranking.

 

[Sniper]

The only advantage (as far as I can see) is the 4 : 1 speed advantage when hand cranking.

Surely, whether 2/1 or 4/1, a turn of the camshaft will only produce 1/2 or 1/4 turn of the crankshaft? I don't see the speed advantage, just mechanical in terms of being able to turn the engine over more easily. Even on a 1GM it is hard work keeping the momentum going without a decent weight flywheel.

 

[DownWest]

Surely, whether 2/1 or 4/1, a turn of the camshaft will only produce 1/2 or 1/4 turn of the crankshaft? I don't see the speed advantage, just mechanical in terms of being able to turn the engine over more easily. Even on a 1GM it is hard work keeping the momentum going without a decent weight flywheel.

The other way round. 1 turn on cam = 2 of the crank. Or 4 with the oddity of 4/1. As earler in this thread, I have hand started many Listers, mostly 2 pot gensets and they always cranked from the camshaft.

 

[Daydream believer]

The Lister and Petter diesels had robust drive to their camshafts so that they could be used to supply power at half engine speed which was convenient for many industrial uses and the starting handle was usually on the camshaft also so a good amount of momentum could be created for starting by hand before closing the decompression lever.

An even faster gearing would make hand starting still easier. That's aside from any industrial use.

To make hand starting as easy as possible the Lister and Petter engines and many others have a means of increasing the fuel supply for starting and a lever for priming the injector and putting some additional fuel into the cylinder. The smaller Petter engines also had a means of injecting oil into the cylinder to increase compression for easier starting.

Injectors in good condition producing a fine mist of fuel make starting easiest also.

I do like to being able to start my old MD7B by hand when the batteries have too little left in them.

I have had at least 25 Lister & Petters diesels & all had a bracket on the flywheel to take the handle for starting. The twin cylinder ones on dumpers & 10/7 mixers were the same.
One had to get them spinning & then flip the decompressor.
I would not want to try turning my 19Hp volvo inboard over but I am sure that if one bolted a stub onto the flywheel of a small diesel one could spin it over even without a decompressor. To an extent the diameter of flywheel is irrelevant as it is the centrifugal force of the spinning mass that carries it over compression

The main problem in a confined space is to watch what you do with the handle once the engine started. One of my Irish groundworkers broke his jaw as he pulled the handle off a mixer & was in effect still spinning the handle & because he was leaning over it to get more power he smashed the end into his face

No one has mentioned the hand start centrifugal starter on 4 cylinder engines like we had on our compressor. I think it had a flywheel on a high gear that one got spinning really fast then engaged a dog tooth gear on the engine. When ever I tried it it just stopped dead but the older stronger labourers used to do it OK & could tell when to swing the engage lever by the whine on the spinning flywheel. Evil thing!!!!!

 

[AngusMcDoon]

To an extent the diameter of flywheel is irrelevant as it is the centrifugal force of the spinning mass that carries it over compression

The diameter of the flywheel does matter because it's angular momentum that carries the engine over compression. Angular momentum depends on the mass of the flywheel and also its size.

 

[Daydream believer]

The diameter of the flywheel does matter because it's angular momentum that carries the engine over compression. Angular momentum depends on the mass of the flywheel and also its size.

Well yes & no
You are right but if flywheels are getting smaller in diameter then they will have to have greater mass
in any event the designers have decided on what they believe is the answer to the problem of maintaining enough force to overcome the compression
So if you have a small or large diameter flywheel it will still operate the same
if you put a handle into a stub on the centre of a flywheel it does not matter if the flywheel is big or small ( forgetting that a heavier flywheel adds to the weight of the engine)
If you want to start the engine using a strap or cord around the circumference of the flywheel then the bigger circumference will give you greater leverage

 

[jwilson]

Well yes & no
You are right but if flywheels are getting smaller in diameter then they will have to have greater mass
in any event the designers have decided on what they believe is the answer to the problem of maintaining enough force to overcome the compression
So if you have a small or large diameter flywheel it will still operate the same
if you put a handle into a stub on the centre of a flywheel it does not matter if the flywheel is big or small ( forgetting that a heavier flywheel adds to the weight of the engine)
If you want to start the engine using a strap or cord around the circumference of the flywheel then the bigger circumference will give you greater leverage

I'm pretty sure that yacht diesel flywheels (whether just the internal starter ring or external) are mostly getting lighter. And flywheel mass and size (often plus decompressors) are critical to hand starting any high compression (eg diesel) engine. You could reasonably easily start 20-30 hp cars in the days when they had starter handles but they were petrol engines with 6:1 or 7:1 compression. I could and did handstart my first car, a Ford sidevalve of 23 bhp.

The old single cylinder raw water cooled 7 hp Volvo MD1 that I had had a big external flywheel and handstarted very easily. That engine weighed about 130 Kg, much the same as my current 3-cylinder freshwater cooled (more gubbins) 27 hp Yanmar 3YM30, which is totally reliant on a working starter motor and charged battery. I do of course have a backup in the form of a rig.

Interestingly the current Bukh engines that are one of the few (only?) yacht diesels that still have handstarts are much heavier than the Yanmar/Volvo equivalents. Maybe it's flywheel mass...

 

[Lakesailor]

Back in my misspent youth, I worked for a landscape gardening firm. We had one of those little dumper trucks with a single cylinder diesel. I never managed to start the thing, despite frequent, often abusive, coaching. It was always started by the oldest member of the workforce, an enormous bull of a man in his late fifties who would casually approach the thing, apply the decompression lever, wind the thing up to speed and crop the lever to be rewarded with a merry tonk tonk tonk and clouds of smoke as the engine caught. It was then left running for the rest of the day to avoid the pantomime of getting it started again.

hmm, I used to have a dump truck like that on the farm. Very useful indeed, but it was also a hand start

If ever starting a diesel with a handle, I would make very very sure that the engagement spline was well oiled and free to rotate when the engine started.

I used to have to hand-start a dumper truck with a very old twin cylinder Lister. This was back when I was a teenager - all testosterone and surplus energy though. The trick was having a stick of just the right length. You'd set both decompressors and wind the handle LIKE MAD. Then, when it was going as fast as possible, You'd have to push the stick with your shoulder BUT KEEP WINDING. The other end of the stick would be wedged against the decompressor for the back cylinder. If you were lucky, it would cough into life and you'd feel it getting easier to turn the starting handle. At this point you knew you could throw the front decompressor and it would be away. Quite a palaver though.

I used to have a high pressure water jetting pump using a twin cylinder Petter diesel. It was hard enough to hand start (we started it using the starter as a rule) but the pump head was permanently in drive so you also had 8 water chamber compressions per revolution to contend with. Even with the feed turned off (you could do that with a Harben pump) it was still hard work,

My friend's father had a 50ft MFV with a huge petrol/paraffin engine in it. It relied on 2blokes spinning the engine over by hand until it was going as fast as they could manage, flipping the compression levers and chucking some petrol into a brass cup to be sucked into the engine.

Once running they left it running until back in port.

 

[Daydream believer]

I used to have a high pressure water jetting pump using a twin cylinder Petter diesel. It was hard enough to hand start (we started it using the starter as a rule) but the pump head was permanently in drive so you also had 8 water chamber compressions per revolution to contend with. Even with the feed turned off (you could do that with a Harben pump) it was still hard work,

My friend's father had a 50ft MFV with a huge petrol/paraffin engine in it. It relied on 2blokes spinning the engine over by hand until it was going as fast as they could manage, flipping the compression levers and chucking some petrol into a brass cup to be sucked into the engine.

Once running they left it running until back in port.

And you try telling kids of today that !!!!!