Can you hand crank a Yanmar?

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Joe Mullee

I'm reading a book about preparing a boat for cruising. In the chapter on engines it goes over emergency starting proceedures. One section mentions having the ability to "hand crank" the engine. Is this possible on a Yanmar 3GMF in an H34? If so, how is it done and where would you purchase the crank? Thanks, Joe Mullee
 

Rick D

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Jun 14, 2008
7,187
Hunter Legend 40.5 Shoreline Marina Long Beach CA
Doubtful

I had a 3GM30. No way. Had an 8HP Yanmar. Yes in that case. With modern high-compression lightweight diesels, no. How old's that book? Bet they teach how to pre-heat a diesel stove too, huh? How about making baggywrinkle? <wink> Rick D.
 
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Chris Webb

Decompression levers on Yanmar

Joe, Check and see if your Yanmar has decompression levers on the top of each cylinder. If so, you can turn the engine over easily with all 3 cylinders decompressed, then close one lever at a time and the engine should fire off. This works well in the case of a battery that's not totally dead but too weak to start the engine normally. Hope this helps. Chris Web
 
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Ron Mills

If I were going

cruising I would not leave the dock without one of the very good battery packs sold everywhere. I carry one in my car at all times in the event something happens to my battery. Additionally, I keep one because alot of people do not like to give you a jump. This would get you out of trouble in the event you have a problem with your battery.
 
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Rich Wallace

With the 3GMF you can if you have a crank

On the front of the 3GMF is a cover which goes over the end of the camshaft. If you take that off you will find that the cam has a hole through it. I am sure that it is set up with the idea tha you put a pin in the hole and then have a crank that will engage that pin. From there you would releave the compression on all three cylinders and while one person would spin the engine another would close the compression levers one at a time. Done right you should be able to start the engine. Having the right crank is the hard part. It has to engage the pin while being able to go over the end of the cam shaft. I suppose that Yanmar had or has them. I never went far enough with the idea to try and find one.
 
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Bill

Nope

Hey, Joe, I got the crank for my 1984 3GMF, and fittings for the shaft a year ago, against Mack Boring's advice. They said I'd never be able to use it, but if I insisted, they'd sell me the parts. They were right, at least with respect to the things I've tried. Including getting the engine turning as fast as I could with all three levers off, and having a friend pop one lever, at which point the engine just stops. However, I did use it successfully to assist the batteries when a bad connection (as it turned out) was preventing all the amps needed from getting to the starter. Since I fixed the root cause of that, I regard the crank to be an interesting though failed experiment. I've heard it said that in a real emergency one might have enough adreniline-induced strength to pull it off. But I learned in the Engine City Technical Institute Yanmar maintenance class a couple of months ago that it takes 300 r.p.m. with compression to start a Yanmar. So I'm skeptical. So I'm contemplating other backup strategies.
 
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Joe Mullee

Bill, 300 RPM's?

I don't think anyone could crank that fast. I guess I'll just keep my Sea Tow membership up to date and make sure my batteries are charged and ready. It doesn't seem plausible to use a hand crank. Thanks to everyone. Joe Mullee
 
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Andrew Brayshaw

Emergency starting

I had the same thought a year ago before I sailed my 34 over the Atlantic. I was on the verge of buying the crank handle conversion when I spoke to someone like Chris who had fitted the same kit and found it impossible to start the engine this way so instead I bought an emergency battery pack capable of delivering 800 amps. It sits fully charged under one of the bunks and is easily capable of starting the engine when all the other batteries are flat. Hope this helps. Andrew
 
Jun 5, 1997
659
Coleman scanoe Irwin (ID)
Careful drivers don't need seatbelts ?!

Whereas I do agree with several previous posters that having good batteries and electronics (in addition to sleeping 8 hrs a night and eating ones wheaties) will reduce the probability of having starter problems, it does not in the least reduce the need to have a backup solution ready, if and when needed. In fact, I think it is safe to predict that sailors who take utmost care of their vessel systems are more likely to have redundant solutions and backup systems built in than sailors who take a rather casual approach to vessel preparation and safety. Have fun, Flying Dutchman
 
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d j

Back up plan yes, crank no

Suggest one practice cranking the engine near a medical facility capable of treating fractures, coronaries, male ego, etc. <grin> Back up for me (worked the last time) is a cell phone to my friends and maybe a jumper cable. I finished up by pulling the boat with my dingy. Previous time I sailed into the dock, which to say the least is a little tricky.
 
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