idling down a 720

(quoted from post at 17:30:38 01/09/15) I have a 1957 720 diesel does anyone know how to
idle down ? l

I suppose that the obvious answer is to move the throttle lever the other direction. But I suspect that there is probably a lot more behind the question. Can you describe exactly what problem you are facing?
 
When the throttle lever is all the way back, the
engine is running to high according to the rmp
gauge it is running about 825 rpms
 
Does the engine have good speed control otherwise? How fast does it run when wide open throttle is commanded? If you select a speed with the throttle does the engine maintain that selected speed with varying load?
 
First off, get a digital tach, that reads off contact, or reflective tape. Put it on the clutch pulley and verify RPM. Then low idle is 700 and high idle is 1250rpm. If you pull the throttle arm back against the stop, without pulling the stop knob out on the dash, and its till high, there is a slotted arm inside the dash, that the throttle arm hooks too. It has a 3/8" bolt with washer, loosen the bolt and bump the linkage a little bit to allow lower RPM's. Set it to 700 against the stop.
 
There is a step by step procedure in the service manual to set up the throttle linkage and then the rack linkage along with it's pivot.
There is a different procedure for the early and late 720 or they will run away.
 
Agree with [b:654c4848f0]Gpower[/b:654c4848f0] 100%.

Take a look at the diagram below.

a178786.jpg" width="650"


Note the 3/8 x 1-/4 cap screw (Key 11) and speed control adjusting arm (Key 13) referred to as the "slotted casting".

Reviewed the SERVICE MANUAL FOR JOHN DEERE DEALERS MODEL 70 DIESEL TRACTOR under the [b:654c4848f0]Slow Idle Speed Adjustment[/b:654c4848f0] topic on page 40-10-6.

"[b:654c4848f0][i:654c4848f0]Slow idle speed of the engine is 700 rpm. It is adjusted at a slotted casting located between the dash and the cranking engine. To adjust, pull the speed control lever back against the stop. Loosen the cap screw at the slotted casting and move arm until slow idle is 700 rpm. Tighten cap screw securely.[/b:654c4848f0][/i:654c4848f0]"

Hope this helps.
 
Does it want to idle at like 1000 rpm with the throttle pulled all the way back and it used to idle normal? Could be that she tossed a governor weight.
 

It has been my experience that FEW 70/720/730 Diesels will Idle slow, like an "R"...
My 720 does not like 700 yet is fine at 750-800,,
Every other thing seems perfect, so I'm not looking for a new project..!!
Idle speed can generally be set at the throttle lever, under the sheet metal. Pretty straight-forward, unless you need to go all the way down to the Injector pumps or Governor..

Ron.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top