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**Wotname** · 15-10-2017, 19:36

Quote:

Originally Posted by buzzstar

Not so much as a confirmation or denial or any position, but I truly wonder why a hand crank for an engine would provide for rotation in either direction. Yes, I understand maintenance, etc., but the engine will start in only one direction, and that is the real purpose of a hand crank for a marine or automobile engine.

There is often a reason for many anomalies

The Yanmar YSx series have different starting rotations even though the crankshaft rotates in the same direction across these series.

The YSE engine is hand started by turning the PTO shaft CCW (viewed from the front). This turns the crankshaft CW.

The YSM engine is hand started by turning the starting gear shaft CW. The starting gear shaft turns the camshaft CCW which turns the crankshaft CW.

Thus in both cases the crankshaft turns CW but the hand crank is turned in opposite direction in each instance.

I'm not sure which way the YSB is turned but I think it is the same as the YSE.

**Wotname** · 15-10-2017, 19:37

Quote:

Originally Posted by Ribman

Sorry if my posts may be detiorating this thread. Please mentally insert many smily emojis and remove any hint of snarkiness.

Hmm... no snarkiness noted at this end

**Wotname** · 15-10-2017, 19:54

Quote:

Originally Posted by buzzstar

Photos are worth a thousand or so words. Please post some. Perhaps views similar to those from the OP. Thanks.

Not exactly what you requested but...

Here is the gear cog that has ratchet style drive which allows it to lock until the PTO shaft is turned by the engine torque rather than the hand start torque. The 4 ball bearings live under the plate on the pulley on the right in little radial slots.

Might get some photo's of the handle later...

nautitrix · 15-10-2017, 19:59

Quote:

Originally Posted by Ribman

Sorry if my posts may be detiorating this thread. Please mentally insert many smily emojis and remove any hint of snarkiness.

Ribman
I have a smiley at the start of the post and no you are not deteriorating anything.
The question I see is, why is the crank designed to fit two different directions. The hand crank on my boat (37 foot) only turns in one direction even though the drive ratchet stops any kick-back. There is no problem with doing a full 360 degree swing as the hand crank attaches at the top starboard on the engine.
Are there any twin engine installations where one of the engines is turned forward to aft and the drive end of the crank is set up with gear on the (front) of the engine? I have never worked on a "v" drive but has anyone ever seen how to hand crank such a tightly installed engine. Someone asked about the room for two hands on the crank handle and yes mine has room for two hands on the handle.

nautitrix · 15-10-2017, 20:06

Quote:

Originally Posted by Wotname

There is often a reason for many anomalies

The Yanmar YSx series have different starting rotations even though the crankshaft rotates in the same direction across these series.

The YSE engine is hand started by turning the PTO shaft CCW (viewed from the front). This turns the crankshaft CW.

The YSM engine is hand started by turning the starting gear shaft CW. The starting gear shaft turns the camshaft CCW which turns the crankshaft CW.

Thus in both cases the crankshaft turns CW but the hand crank is turned in opposite direction in each instance.

I'm not sure which way the YSB is turned but I think it is the same as the YSE.

We can accept that we can hand-start our engines. I am so glad that someone has resolved why the hand-crank is bi-directional. It makes perfect sense from a parts engineering perspective.

Rock-Head · 15-10-2017, 20:28

Quote:

Originally Posted by Wotname

I'm not sure which way the YSB is turned but I think it is the same as the YSE.

FWIW my SB12 turns CCW.

And the hand crank looks nothing like the OP's pic.

**Wotname** · 15-10-2017, 20:37

Quote:

Originally Posted by nautitrix

We can accept that we can hand-start our engines. I am so glad that someone has resolved why the hand-crank is bi-directional. It makes perfect sense from a parts engineering perspective.

I don't know but I'm guessing the bi-directional crank was introduced with either the YSM (or SM) as it would be backwards compatible to the earlier YSE / YSB and probably the SE & SB.

EDIT: There is a swag of other industrial small diesel engines made by Yanmar and presumably some of these used hand cranks.

**Wotname** · 15-10-2017, 20:39

Quote:

Originally Posted by Rock-Head

FWIW my SB12 turns CCW.

And the hand crank looks nothing like the OP's pic.

Curious, what does your SB12 hand crank look like?

And does it turn the camshaft, crankshaft or some other PTO shaft?

nautitrix · 15-10-2017, 20:48

I wish I could afford one of these, but they look like the only way to hand-start a 4-108.
The Startwell Mini – Startwell Engineering
For the record, my hand-crank does not look the same as the photo but it is for a larger engine.

Rock-Head · 16-10-2017, 04:52

Quote:

Originally Posted by Wotname

Curious, what does your SB12 hand crank look like?

And does it turn the camshaft, crankshaft or some other PTO shaft?

Its a short, hefty little bugger about 8" long and attaches to a through-pin on the crankshaft. Twin dog slots with the tapers that throw the handle off the crankshaft. I'll grab a pic next time I'm down at the boat.