Hand cranking diesel

Ed Schenck · Jul 31, 2011

Are you saying your engine is not set up for hand cranking? My old 2QM20 had the hardware but I don't know anyone ever being successful hand starting. You can see the chain-drive to the crankshaft in the photo.

Hermit Scott · Jul 31, 2011

DaveM said:
Maine Sail

You mentioned in another thread being able to hand start a diesel on a boat if necessary. I agree and have been looking for a process to hand start a M25XP on an O'Day 35 and therefore have a decompression lever. There is a lot of room in front of the crankshaft pulley. What would be the approach.

Thanks
DaveM

You better have a finely tuned engine to hand crank it.

MLampner · Jul 31, 2011

My YSB 12 similar to Ed's 2GM had the setup. I tried on several occasions but never figure how you were supposed to spin the engine with the crank and keep the compression release down. The arc of the crank took it right where your other arm would need to be control the compression release. Suffice to say despite the attempts I never even got a single pop and that was on a very small 1 cyl engine can't imagine trying to get something bigger spinning fast enough that it would fire.

Stu Jackson · Jul 31, 2011

Dave, I really wouldn't do it or even try to. You're too nice a guy to risk getting hurt.

For years the C30 Mainsheet tech notes kept stressing the use of the decompression lever on M25 series engines. My personal read on that was that they didn't trust, or build, a good electrical system, and the folks writing those tech notes were earnest and cared about their boats, but they didn't, in retrospect, know much about electrical systems on boats.

Our response has always been to build a good electrical system with the appropriate "Backup " (like a simple 1-2-B switch with a separate reserve bank with the echo charger or other type of relay and the B position as a backup for the relay and never used when running, with the AO to the house bank).

I find it far, far safer.

kloudie1 · Jul 31, 2011

I think Maine's intent was to make the poster aware that the statement that he could start his engine by hand crank may not have been valid. The poster had a battery set up that allowed all batteries to be drawn down (no reserve start or house batt) and in his post explaining why he had it that way, poster said that he wasn't worried because he could hand crank his engine to re-charge.
I have seen small diesels around 10 horsepower hand cranked, but they were in mud boats that had unrestricted access to the front of the engine. (naked engine sitting on the floorboards) The guys would pull the decompress lever, then give the engine 10-12 revs of hand crank to try to get it spinning as fast as they could.. then put the compression back on.. The issues in a sailboat would be enough room to be able to fully rotate the crank without hitting something and to have enough access room to put enough "umph" in it to get it going. Spinning with low batteries while decompressed and then putting the compression on is a much better alternative ..but ya still have to have a little left in the batts for that to work.. I carry one of the little portable jump starters as my "just in case"..

gmeyerga · Jul 31, 2011

I have a tinker toy Yanmar 1GM. When decompressed I can spin it like a
top with my crank. When I release the decompression lever it stops dead.
Has anybody ever handstarted a diesel without am big flywheel?

Maine Sail · Jul 31, 2011

DaveM said:
Maine Sail

You mentioned in another thread being able to hand start a diesel on a boat if necessary. I agree and have been looking for a process to hand start a M25XP on an O'Day 35 and therefore have a decompression lever. There is a lot of room in front of the crankshaft pulley. What would be the approach.

Thanks
DaveM

My point was not that you "should" be able to hand start your motor but rather that you "should" have a darn good reserve battery system because even on hand crank equipped marine diesels I have yet to find anyone who could do it reliably.

For an M-25, it needs glow plugs so you really better be very, very strong and be able to rub sticks together very fast in order to replace your battery & glow plugs....

With a well thought out electrical system you should never need to hand crank your motor, or even think about it.

Maine Sail · Jul 31, 2011

DaveM said:
Stu and others

I appreciate the concern. And believe me attempting greatly concerns me to the point that I wouldn't try it unless I know it can be done safely. That is why i am asking. It is just the pilot in me being prepared as I can. There is another thread "electric plan omissions......." that this came up on by MS saying in an options list:

"1- Be sure you can hand start that engine. I've yet to meet anyone that could, when needed, in a sailboat. Hand starting an engine on a lee shore with an anchor dragging and a dead bank may not be able to be done in-time.."

That was a direct response to someone who wants to use one bank of batteries because he thinks he can hand start his motor and does not need a reserve bank. My point was "be sure you can hand start that engine" before throwing a reserve bank out the window as an option. I seriously doubt he'll be able to and that was my point..

Don't bother trying to go the hand start route...

Stu Jackson · Jul 31, 2011

Whew...

Good news, guys. Dave, that's what I knew (thought?) he meant all along.

I sholda known those glow plugs were a dead giveaway.

Thanks,

Stu

Sailm8 · Aug 1, 2011

I have been able (one time) to start my 1gm10 by hand. The PO had welded an extension on the hand crank to get it further from the front of the engine. This let me stoop over to crank rather than kneel. My wife held up the decompression lever while I cranked like hell. It worked.

jackpot · Aug 1, 2011

starting a diesel

A mechanic taught me this trick, don't know if if will work on your engine, but..

you can create an arc with a screwdriver to start it, if you want, I can send a pic with details

Capn Ellis · Aug 1, 2011

Maine Sail said:
Don't bother trying to go the hand start route...

So ... your batts are double-banked-isolated-fool-proofed and good to go. Now the starter coil shorts and welds the armature to the frame. Oh-oh.

I'm just sayin'

JVB · Aug 1, 2011

Hand cranking a gas engine can result in a broken wrist from a kickback. Same for diesel ?

woodster · Aug 1, 2011

Maine Sail said:
Don't bother trying to go the hand start route...

i personally think that the hand crank set up is only useful in adjusting the valves...with the compression release..other wise its a total waste of energy and time.....jmtc ....

regards

woody

CHARLIE STAGE · Aug 1, 2011

I go with the jump box and low batteries on my Yanmar 3GM30 F. I have an old 1000amp jump box and the two times I have been caught with very low batteries, it was decomp up, power on starter, drop the decomp and she starts like new. Battery charge to follow and whew!!

Ed H · Aug 1, 2011

CHARLIE STAGE said:
I go with the jump box and low batteries on my Yanmar 3GM30 F. I have an old 1000amp jump box and the two times I have been caught with very low batteries, it was decomp up, power on starter, drop the decomp and she starts like new. Battery charge to follow and whew!!

Do hook the jumper cables to the starter or to the dead/low batteries? Ed H

Hand cranking diesel

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