8V71 idle help

[TheMightyQuinn]

How do you adjust the idle on an 8V71? Ist in a 4106. Cant get into any gear unless i turn it off first. Also need to check the clutch adjustment but dont know how to do that either. Thanks in advance!

[eagle19952]

in neutral the idle shouldn't really matter...sort of... if you have no clutch brake or you are totally out of adjustment.. you could probably be idling at 100 rpm and still never engage 1st gear while running.
What is your idle set at now ?

My bet is you have no clutch brake...and your linkage is out of adjustment.
Normally the idle on a Detroit is set and there you go ... set for life....

But, not being fully versed on your coach... I could be wrong...I was once..

[bevans6]

There are several on-line manuals that tell you how to adjust the idle on a DD 8V-71, unfortunately it's not a one line explanation and parts of it have the potential for being expensive.  It's part of a general tune up.   No clutch brake on your bus, and if the clutch drags it can be impossible to shift into first with the engine running.  The GM guys can direct you to advice on how to adjust your clutch.  Sorry not to be of more help.  This link might work, or google 8V-71 adjust idle

https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0ahUKEwiJxuvIvvPLAhVIbR4KHUJUDyUQFgg8MAY&url=https%3A%2F%2Fbrandon314.files.wordpress.com%2F2012%2F05%2Fdetroit-6-71-valve-injector-and-governor-adjustment-procedure.pdf&usg=AFQjCNHcGA7YCg5PfPWFWEeIowkLWenggg&cad=rja

Brian

[TheMightyQuinn]

in neutral the idle shouldn't really matter...sort of... if you have no clutch brake or you are totally out of adjustment.. you could probably be idling at 100 rpm and still never engage 1st gear while running.
What is your idle set at now ?

My bet is you have no clutch brake...and your linkage is out of adjustment.
Normally the idle on a Detroit is set and there you go ... set for life....

But, not being fully versed on your coach... I could be wrong...I was once..

Yeah i come from the gas burner world so this whole deisel thing is totally new to me.

There are several on-line manuals that tell you how to adjust the idle on a DD 8V-71, unfortunately it's not a one line explanation and parts of it have the potential for being expensive.  It's part of a general tune up.   No clutch brake on your bus, and if the clutch drags it can be impossible to shift into first with the engine running.  The GM guys can direct you to advice on how to adjust your clutch.  Sorry not to be of more help.  This link might work, or google 8V-71 adjust idle

https://www.google.ca/url?sa=t&rct=j&q=&esrc=s&source=web&cd=7&ved=0ahUKEwiJxuvIvvPLAhVIbR4KHUJUDyUQFgg8MAY&url=https%3A%2F%2Fbrandon314.files.wordpress.com%2F2012%2F05%2Fdetroit-6-71-valve-injector-and-governor-adjustment-procedure.pdf&usg=AFQjCNHcGA7YCg5PfPWFWEeIowkLWenggg&cad=rja

Brian

Cool pdf, saved. Thank you! Yeah its definitely dragging as i tried to start it in first and the bus jerked, so definitely out of whack! I have a few days of dry weather so im hoping to get this baby freed from the swamp of a back yard and into the driveway.

Thanks for the replies!

[chessie4905]

Did it just jerk or did it kill the engine or won't it start while in gear with pedal down? Could be stuck to pressure plate or flywheel. How about idle till air is up, release brakes, stop engine put it in gear with clutch out and start it and once it is moving, push clutch in. If it doesn't release then, hold clutch in and apply full engine power for a second or two to release it. First, do watch linkage at engine while someone pushes pedal down. There should be a little free play at the pedal, maybe an inch before release  arm actually starts moving  throwout bearing and significant increase in pedal pressure.

[TheMightyQuinn]

Did it just jerk or did it kill the engine or won't it start while in gear with pedal down? Could be stuck to pressure plate or flywheel. How about idle till air is up, release brakes, stop engine put it in gear with clutch out and start it and once it is moving, push clutch in. If it doesn't release then, hold clutch in and apply full engine power for a second or two to release it. First, do watch linkage at engine while someone pushes pedal down. There should be a little free play at the pedal, maybe an inch before release  arm actually starts moving  throwout bearing and significant increase in pedal pressure.

Yeah it jerked the whole bus forward and wouldnt start. Put it in neutral and it fires up. Wont go into any gear at any speed. We had it moving around the yard. It was in the back of a field for about six years lost in the bushes sinking in the mud.
The accelerator cable is totally rusted in the tube somewhere.

Ill have my friend mess with the clutch pedal tomorrow morning and ill check at the tranny.

Air leaks, it has plenty on top of the two already blown bags.

Thanks for the help y'all. I got some reading and messin to do tomorrow morning.

[chessie4905]

I thought the tube the throttle cable was in is made of brass to avoid rusting. Make sure the problem isn't at the bellcrank or at the engine area. It could be worn through the tube where it makes a bend behind the engine.

[TheMightyQuinn]

I thought the tube the throttle cable was in is made of brass to avoid rusting. Make sure the problem isn't at the bellcrank or at the engine area. It could be worn through the tube where it makes a bend behind the engine.

Again im totally new to deisel stuff and big buses so you are probably correct. It is disconnected at the engine and at the pedal assembly. The cable wont budge at all. What is this bellcrank and where might i find it? From what i can see up front it looks like a metal line is going to the bracket the cable bolts to, then disappears into the body, and ends up as a definite cable at the engine. I cant get photobucket to work on my phone, and i dont have a computer or id have pictures for reference.

[eagle19952]

Again im totally new to deisel stuff and big buses so you are probably correct. It is disconnected at the engine and at the pedal assembly. The cable wont budge at all. What is this bellcrank and where might i find it? From what i can see up front it looks like a metal line is going to the bracket the cable bolts to, then disappears into the body, and ends up as a definite cable at the engine. I cant get photobucket to work on my phone, and i dont have a computer or id have pictures for reference.

Here is a little tidbit I do know...IF you remove the cable..to do anything...it is my understanding that there are two adjusting/retaining wedges... the are made of unobtainium...not to be lost misplaced or given to anyone  (but yourself) to mind, safe keep, or otherwise forget...

[TheMightyQuinn]

Here is a little tidbit I do know...IF you remove the cable..to do anything...it is my understanding that there are two adjusting/retaining wedges... the are made of unobtainium...not to be lost misplaced or given to anyone  (but yourself) to mind, safe keep, or otherwise forget...

Gotcha and thanks for the heads up. Got some wiring to figure out then ill hopefully get her moved to some harder ground so i can actually work on this thing. The cable is seized somewhere in the body so when/if i get it out ill keep an eye out for those clips.

Anyone have a wiring diagram for a 4107 by chance? All the cloth wiring from '66 has faded to the same color

[Scott Crosby]

There is a video on my YouTube Chanel that shoes hot to,remove the cable.  It's really easy.

Check out this video on YouTube:

http://youtu.be/sZ05IXUSbKU

[TheMightyQuinn]

There is a video on my YouTube Chanel that shoes hot to,remove the cable.  It's really easy.

Check out this video on YouTube:

http://youtu.be/sZ05IXUSbKU

OMG awesome! Id have disassembled everything before i found that out! Thank you!!!

[TheMightyQuinn]

Ok, got the cable out no problem. Actually looks like its recently been serviced? Anyways, its at the front slide-ie mechanism. I have the u-bracket disconnected from the pedal and pivot assembly which all moves free. If the front end is the same as the rear the bigger tube with the u bracket should grip the cable and slide on a smaller tube forwards, correct?ive sprayed a can of penetrating oil on the end where the smaller tube goes into the bigger one.

Yall are awesome!

[TheMightyQuinn]

Ok, after breaking some 550 parachute cord and two expensive ratchet straps ive finally gotten the front assembly apart, cleaned, lubed and reassembled. Got pedal now, yay!

Replaced the starter solenoid. Found my short... Now she fires up perfectly everytime.

Still cannot get this pig into any gear at any time. Tried flooring the engine to try and free up the clutch, no luck. Tranny speeds up. Definitely not disengaging. It worked a week ago when we pulled it out if its grave, but now nothing. Can someone please give me the procedure for adjusting this mechanical nightmare? Im running out of time to be able to rescue this thing and move it off of this property. Either that or is anyone around the north atlanta suburbs??

[buswarrior]

Did you try to get it into ANY gear?

With some of these, you couldn't readily get into 1st at a stop, slipped into 3 or 4 and then slide to 1st kept the grinding noises to a minimum.

Never took it out of gear, always slipped to first as you rolled to a stop, clutch in the whole time at the light.

Those were the days.... sure was fit...

happy coaching!
buswarrior