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15-11-2007, 07:57
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#1
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Registered User
Join Date: Oct 2005
Posts: 6,185
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hand cranking a 52hp yanmar 4JH2E
Hey folks. I was reading one of my sailing books last night, and it said that "most marine diesel engines have a hand cranking option, make sure you understand it."
So I googled around, and didn't find much, except for this, and then I found some hand cranks on yanmar's parts list, so I know they exist.
Collected Wisdom - Hand starting a Yanmar 3QM30H(F)
The general vibe on that web page is that although it works for smaller diesels, the bigger ones take too much force. Maybe that's the case, but I wanted to ask around before I threw the idea out in total. If I can rely on a metal crank instead of an elaborate eletrical redundancy system in the event my starter doesn't kick over, I'd like to.
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15-11-2007, 08:30
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#2
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Registered User
Join Date: Mar 2006
Posts: 1,594
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My 6.5hp 1GM has a handcrank AND I've used it to start the motor just to see how hard it was. It wasn't too difficult. BUT on your big 4 banger, I don't know....Can you crank and hold the compression release at the same time?? If not then you'll need at least a helper....
I agree 100% in the pleasure derived from knowing that I can start my 1GM without a lick of 12V....
I'd give it a try if I were you.....
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Randy
Cape Dory 25D Seraph
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15-11-2007, 09:36
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#3
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Registered User
Join Date: Oct 2007
Location: Lakewood Ranch, FLORIDA
Boat: Alden 50, Sarasota, Florida
Posts: 3,467
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It is not possible to hand crank a 4JH engine. There is no compression lever to release pressure and no practical way to mount a hand crank with sufficient leverage to overcome the compression. Most of the older how-to books make mention of hand cranking but is is possible only on the smaller engines and those designed to allow it.
A redundant electrical system to ensure power to crank it isn't very complicated - a separate start battery direct wired to the engine is all you need and on any boat with this sized engine, space should not be an issue.
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15-11-2007, 09:44
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#4
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Registered User
Join Date: Oct 2007
Location: Kelowna , British Columbia
Boat: Corbin 39 Pilot House, Tayana 42
Posts: 294
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Years ago when in the army we were cranking gas motors on the trucks, but if one wasn't careful and experience enough , the kicking back crank would broke your rib cage in half . For a fifty $$$ you can get the buster battery with flashlight, radio , etc. If you can't start your diesel you can at least listen to the radio .
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15-11-2007, 09:46
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#5
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Registered User
Join Date: Oct 2005
Posts: 6,185
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Yeah, I know a seperate battery isn't that big of a deal, but if a crank was possible, it's even more straight forward, since it's just a metal bar with a socket on one end and a rolling handle on the other.
I already submitted my question to yanmar, but everyone here, and everything I've read elsewhere, indicates this isn't possible. I honestly wish I could have a smaller engine that did allow it though.
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15-11-2007, 09:58
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#6
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Registered User
Join Date: Jun 2005
Posts: 1,901
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What do they sat in Jersey......fugetaboutit.
I don't know a human alive that can generate enough energy to turn over a 4JH.
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15-11-2007, 10:11
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#7
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Senior Cruiser
Join Date: Dec 2003
Location: Marlborough Sounds. New Zealand
Boat: Hartley Tahitian 45ft. Leisure Lady
Posts: 8,038
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You could try, but it will be only the once. Either you will give up on the first attempt, or worst case, you get it just far enough to fire and you will end up with two broken wrists and for a split second, be in wonderment as to how far and fast you can travel across the engine room.
It varies greatly from design to design, but you can be expecting a compression of about 10000PCI at full squeese.
__________________
Wheels
For God so loved the world..........He didn't send a committee.
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15-11-2007, 11:28
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#8
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Registered User
Join Date: May 2006
Location: Nicholasville, Kentucky
Boat: 15 foot Canoe
Posts: 14,191
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I've started several two cylinder Volvo engines that had compression release on them. They also have really large heavy flywheels like the old "popping Johnies." It can be done. I wouldn't even try a 4 cyl without compression release. Way too hard to spin fast enough to fire.
JohnL
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15-11-2007, 11:47
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#9
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Registered User
Join Date: Nov 2007
Location: SE Asia
Boat: Belize 43
Posts: 15
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If your battery's flat - you can always put your hand over the air intake to lower the compression and get the thing moving, then release your hand when cranking speed is up and off you go. Be careful not to lose your hand though!
Tricky.
S.V Lionheart
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15-11-2007, 13:18
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#10
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Registered User
Join Date: Dec 2006
Location: Seattle
Boat: Cal 40 (sold). Still have a Hobie 20
Posts: 2,944
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Quote:
Originally Posted by rebel heart
Yeah, I know a seperate battery isn't that big of a deal, but if a crank was possible, it's even more straight forward, since it's just a metal bar with a socket on one end and a rolling handle on the other.
I already submitted my question to yanmar, but everyone here, and everything I've read elsewhere, indicates this isn't possible. I honestly wish I could have a smaller engine that did allow it though.
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Kind of expensive, but if you want another way to start your engine:
Spring Starter Easy Diesel Hand Starting from Kinetico, the lightweight hand starting revolution begins here
There are probably other companies, but this was the first that came up on spring starter search.
I have a couple of friends that took a diesel repair class. One of the things they got to try was hand cranking a Perkins 4-107 I believe. This engine was not in a boat, it was possible to plant your feet and arrange yourself to the best position. No one in the class could start it.
John
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15-11-2007, 16:52
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#11
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Registered User
Join Date: Oct 2007
Location: Caribbean Sea
Boat: Island Packet 40
Posts: 42
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Hand Cranking--Don't do it!
I shipped out commercially on anything from 600 to 900 feet. One of my duties was to start the lifeboat diesel like once a week. It was a hand crank job and damn tough. The diesel was tiny, maybe 5 or 6 hp and had compression release levers. It was much, much easier if you had someone with you to throw the levers when it was up to speed. When the oil was cold, like on the North Sea, it was much more difficult.
On an engine the size of a 4JH, I would not attempt this. The torque of this engine is massive when compared to a small single cylinder unit.
That being said, I pull started my 200 hp Yamaha outboard on one occasion. Pull the cowling, wrap a piece of line around the flywheel, and let her rip. I was surprised it was so easy. This was not the same as a diesel though!
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