Engine Idle Set Screw adjustment

[army70deuce]

Following another post I submitted about my low idle of 400rpm the suggestion was posted that I adjust the idle set screw, upon attempting to change the setting I realized that the set screw had already been adjusted previously to the point where screwing it in any more failed to accomplish anything. Please take a look at the pictures I am posting and let me know of any suggestions. Thanks

Feel free to download and edit my pictures and re-post them with suggestions.

1970 AM General
M35A2
Idle = 400rpm give or take.


Previous Post

http://www.steelsoldiers.com/deuce/42923-engine-questions.html

 

[chris837rj]

I don't know what the problem is off hand. Do you still have normal power at speed or under a load? Maybe the IP is worn to the point that it is leaking fuel around the piston? Could be a linkage problem in the unit, something bent that idling up will not completely compensate for? I would think it would be a simple adjustment though. The control lever has notches to be adjusted and the idle adjustment arm likely has the same thing. If you take both arms and rotate then a notch or two clockwise and put everything together you should have an increase in rpm's at idle. You can then back off the idle screw and everything will be normal. I would lean more to that problem if the truck had this problem since you bought it though.

 

[doghead]

Do you have fresh fuel and fuel filters? Is your in-tank pump giving you 3-5 psi at the secondary filters?

If your other thread has info on this problem, maybe a link to it would help? or just continue that thread?

 

[army70deuce]

The deuce drives fine and has good power and appropriate rpm when I'm driving. it is just at idle when I'm not giving it any gas that it idles/struggles at 400rpm. The Idle Set Screw was at its current position when it was delivered. It arrived with an almost empty tank so it does have a few gallons of fresh fuel but I have not switched out the fuel filters yet. I'm really wondering why the idle set screw was set to its current position when I received the deuce.

 

[doghead]

Well, It may just be indexed incorrectly. I guess I would try to readjust the arm so that the idle screw does not need to be in so far.

 

[poppop]

I think I suggested adjustting the screw. I don't know why it is like it is, so no help there. If it were my truck and everything else seemed OK, I would see if I could use the hand throttle cable as an idle adjustment. Push the handle all the way in, Loosen the screw in the clevis on the pump and slide it until you get the speed you want and tighten the screw. Should work.

 

[G-Force]

if you look in TM9-2910-226-34 in section 3-40 there is an exploded view of the throttle linkage. That idle stop cam assembly is secured to the throttle shaft with a bolt that pinches the stop assembly onto the splined throttle shaft. There is also a snap ring in front of the cam assembly. Remove the throttle arm and see if the split in the stop cam is in line with the line that is scribed on the end of the throttle cable. I think you'll find that it isn't. All you have to do is reorient the stop cam on the throttle shaft to align the split in the cam with the line that is svribed in the end of the throttle shaft. But watch because you might gain rpms at the top end and may need to readjust the high speed stop. Check I think page 3-54 of the TM. I think it shows the orientation of the stop cam on the shaft. Let us know how you make out.

 

[army70deuce]

G-Force,
After reading over the TM earlier I was wondering if that was what I'd have to do. Thank you very much for the detailed description/instruction on what should be checked and changed, also thanks for listing the section of the TM in your response, I had downloaded it from the resource section earlier and you pointed me right to where I should look. I will be working on it in the morning when it gets light outside and post what I find and if it works. Thanks

 

[WillWagner]

I have an extra pump. I went and looked at it and the stop cam split is not aligned with the line on the shaft. The pump came off of a running engine...till it spun a bearing! It is too dark here to go look at the truck and see where the line and split are on that. How's the high idle, no load RPM? Should be around 2900-3000. If it were mine, i'd re locate the stop cam to the position in some pics to follow...sorry, i'm not on my PC and for some reason, the camera won't load with a USB...but the cam is turned 4 splines to the front of the engine. That should bring the stop cam to the proper position so the screw contacts the cam. You might need to re set the high idle, no load RPM. It will be too high when the cam is moved.
Pics to follow soon.

Sorry, 4 splines to the REAR!

 

[army70deuce]

On mine there isn't a line to line up anyway, if you look at the 1st picture I posted you'll see it has a hole instead of a line. I've taken off the operating lever, the cover, and the split ring as well as the idle and max set screws, problem is that the allen screw that holds the cam on is stuck. I let it soak in WD40 for 15 min and tried again but I feel that I'm either going to strip the allen head or snap the allen wrench in my hand.(yes I'm wearing leather gloves) so at this point I'm just letting it soak for a few hours, I hope I won't have to drill it out because that will be near impossible while everything is still in the engine compartment.

 

[WillWagner]

Try a bit of heat, A small propane torch will do the job.

 

[army70deuce]

I just realized that I never gave a final condition on this so here's my very late update. The splines(think that is the right word) on the inside of the rocker are pretty worn so when the engine was running and vibrating the splined shaft would slip inside it and eventually it would keep getting lower and lower. I finally reset it and tightened the **** out of it and it's been running pretty good. Eventually I'll need to take it off and go find a replacement at the local deisel engine shop if they have one, otherwise I'll see what suppliers carry that part.

Once again thanks for all the help