Stopping the Diesel Engine

[James Howell]

On page 10-10-3 of our Model 70 Diesel tractor service manual is the following paragraph:

<blockquote>[b:654c4848f0][i:654c4848f0]To stop the engine, pull out speed control lever stop button on dash and pull speed control lever all the way back (Figure 10-10-5). The purpose of the stop button is to permit moving the speed control lever to the idling position without stopping the engine. When speed control lever stop button is pulled all the way back, the fuel supply to the engine is cut off and after a few revolutions, the engine will stop.</blockquote>[/i:654c4848f0][/b:654c4848f0]

The method describe above is the way I shut down "Big John" our 55 Model 70 diesel.

The photo below shows the "farmer tech" decompression lever on our tractor.

<a href="http://s200.photobucket.com/albums/aa5/jameslloydhowell/John%20Deere%20Equipment/Big%20John%20and%20Krone%20260/?action=view¤t=IMG_2939.jpg" target="_blank">

</a>

Rather than using the method described above in the service manual, if the decompression shaft lever is pushed forward and relieves compression in the diesel engine, will this method of stopping the engine cause any damage to the engine?

 

[55 50 Ron]

That lever gets pulled rearward to release compression. Or has yours been modified somehow?

I know of people who do release the compression (AFTER shutting off the fuel) and then let the engine coast to a stop. This method will not cause any damage to the engine.

 

[MSD]

Supposed to be better for the flywheel not wearing on the crank if you just let it coast when stopping it by decompressing. Or so they say.

 

[LarrySTN]

55 50 Ron...Actually the lever pictured on the side of the crankcase moves forward to release the compression..not backward.

 

[jd2cylman]

(quoted from post at 20:52:30 11/27/11) Supposed to be better for the flywheel not wearing on the crank if you just let it coast when stopping it by decompressing. Or so they say.

Not better for the flywheel, but better for the ring gear. Two-cylinder diesels mainly stop in two places. By using the decompression lever at shut down, the engine freewheels to a stop, increasing the chances that the starter gets a fresh (or at least fresher) spot on the ring gear rather than always at the same two places. On both of my diesels, I removed the ring gear and rotated them 1/4 turn. But I still pull the decompression release to stop the tractors.

 

[NW MO Poppers]

My 70 diesel has had a foot pedal welded to the original linkage for that very purpose. I always use it to shut down, after the steps described in the manual. I bought the tractor from the original owner, and he said he put the foot pedal on about 5 years after he bought the tractor, at the recommendation of the local JD dealer, to save the flywheel splines.
My have helped, but I still had to replace it with a taper-lock when I bought it. But, it was also 50 years old, so whadda expect

 

[old popper]

I always decompress after pulling out the stop button and pulling throttle lever all the way back on my '57 720. Hasn't hurt anything yet.

 

[buickanddeere]

Splines are fine without decompressing during shutdown.
Spline wear occurs when some hack removes and installs a flywheel without using a torque wrench.

 

[buickanddeere]

The wife has a pair of cousins and an Uncle who never be asked to design rockets for NASA.
They purchased 730 D years ago when two cylinder collecting became popular. One day they were showing to us but were real insulted. When I asked just what kind of a dumb _ _ _ _ shuts the 730 down that way.
They were just pulling the de-compressor to stop the diesel.
They were dumbfounded when I pulled the shutoff stop and moved the throttle to the zero rack position.

 

[buickanddeere]

Is that a set of "farmer fix" ignition coils on there ?

 

[Mike Aylward]

Exactly right. The power pulses of the engine would do more damage than a momentary rocking of the engine at shutdown. It's commonly done anymore but I don't subscribe to the reasoning. Mike

 

[Anonymous-0]

When I shut my R down I shut the fuel off and then pull the decompression lever to let it slowly coast to a stop. When I was a kid and shut down dad's R I shut the fuel off and got off. Bud

 

[James Howell]

Yes, there are four 6 volt coils mounted above the motor.

Came that way when we bought the tractor.

No coils in the pony motor distributor.

Maybe some day I'll get around to replacing the pony motor coils.

 

[Mike M]

You likely have better "fire" from what you have on there.

If you go to all the expense of changing it back to original it just may not work as well.
Those car coils just look like heck ,but sure do work better. Especially if the pony is getting worn out.

 

[James Howell]

One of the breaker points in the distributor was bad and pony would not start; no spark to the either plug.

Robbed a breaker point from our spare pony distributor and replaced the bad one.

Made s rooky mistake of holding coil wire while testing for spark; coil was putting out a long, hot blue spark.

Pony motor ran good and tractor fired right up.

 

[James Howell]

Thanks for all of your replies.

I'll continue to shut down the tractor according to the directions in the operator's manual and will also relieve compression as it runs out of fuel.

 

[55 50 Ron]

Larry,

Thanks for the correction! I was thinking of the lever that is pulled back when the decompression is activated. I knew better but didn't think clearly!