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1979 C&C 30 Mk I - 2QM15
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Discussion Starter · #1 · (Edited)
On a Yanmar 2MQ15 specifically... If the hand crank fitting on the front of the engine is broken off. How big of a job is it to replace this? Is it as easy as buying a replacement, unscrewing the two mounting screws, and popping on a new one? Or is there something more behind there that's going to add a lot of complexity to fixing this issue?

My limited understanding of diesel mechanics, (which may be incorrect), is that the hand crank is necessary whenever you need to bleed the engine.
 

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i have a 1gm and tried to start my motor with the crank. it took my wife holding up the decompression lever then dropping it at the right time, and i had run the motor about 20 mins before, and it took about 5 tries.

honestly dont bother with it, if you want to try it come up to the inner harbor and try it on my boat.
 

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1979 C&C 30 Mk I - 2QM15
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172 Posts
Discussion Starter · #3 ·
From what I've Googled... I don't think I'd ever want to try "starting" an engine via the hand crank. But I've read that it's useful for certain maintenance activities that require bleeding the engine afterward, or am I reading those posts incorrectly?

Would there ever be an instance where using a manual hand crank would be better than just running the starter motor to bleed the engine?
 

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i guess it would make it easier for some things. when i bleed the fuel system on my boat i used the little primer pump on the fuel pump, took me 5 mins to do. yes you dont want to crank the starter for more than 5 seconds every 30 or so ( my numbers i use YMMV ) to help not heating it up. but i dont think you will really need it, if you lift the decomp levers and hit the starter the motor will spin like crazy. just a second of cranking like this will do lots of bleeding.
 

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A 2MQ is a 15hp and a 1 is a 10hp, correct ?

Are Yanmars especially difficult to hand start ?

We have a Bukh 24hp in our old girl and you can hand start the thing from dead cold, no problem at all. I find it hard to believe that a 15hp would be problematic. Throw open the decompression lever , spin the bugger and recompress. Never fails. One person job. Admittedly very mild climate.

OK, so once you get over 25hp hand starting is usually not an option but smaller engines can be hand started easily. In my previous boat the batteries died on me at a time when I couldn't afford new ones and I would hand start the engine every time I took her out. That was a 15hp Volvo Penta. A child could do it.

Replacing the hand crank unit on the Bukh is a simple task so again I'm presuming the same would be the case with the Yanmar.
 

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If you need to turn the engine to bleed, put a socket on the crank pulley. I wouldn't go to the expense of replacing the broken crank parts just to bleed.

And, as another post correctly said, if the starter is working, spin the engine with the decompressors down and it'll bleed real easy.
 

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You do not need to turn the engine over to bleed. As mentioned above, just use the hand lever, on the mechanical fuel pump.

As Andre mentioned, you can use a socket on the crank, (or turn the belt by hand, with the decompression levers on) if you need to slowly turn over the engine for other reasons.

TDW- maybe Yanmars have higher compression, or something, but it is not easy to hand start my 15hp 2GM. I only tried once, and had my girlfriend throw the dcompression levers, once I had it spinning good, but no go.

I think I could do it if I had to, but it wasn't worth hurting already bad shoulders just to see if I could!
 

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A 2MQ is a 15hp and a 1 is a 10hp, correct ?

Are Yanmars especially difficult to hand start ?

.

I have Yanmar 2QM15. I couldn't hand start it. At some point my starter died while I was at sea. I spent a day, trying all possible ways to crank it. As soon as decompression lever released, engine stops, there is no way to crank it through the compression more than once. I guess that the flywheel is too light, there is not enough inertia.
There is some situation then you may need hand crank to bleed fuel lines, such as if you are trying to get air from lines anywhere between high pressure pump and injectors. In this case you can spin it with a starter.
Also hand crank is needed for valves adjustments. There is no way to avoid it, however, I think, it is possible to rotate the wheel by belt.
 

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About the only time I've seen hand cranking works is on Charlie Chaplin and those Keystone Cop show. For the life of me, I couldn't crank start my 2GM20F. What a load of bull from Yanmar selling me the hand-crank option.
 
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