JD 70 gas throttle

On a 1953 JD 70 gasoline, I was having trouble with the throttle moving back a little when running at full idle. So after looking into it, I found two worn out friction discs, and a broken spring. I replaced the plate along with 2 new friction discs, and a new spring. I tightened the spring so that there are about 10 lbs. of pull at the end of the throttle like the book calls for. At fast idle or wide open as some would prefer, the throttle comes back just enough so that my best guess is that I am losing maybe 50-75 rpms. Any thoughts on what I can do for adjustment with the linkage between throttle and governor, or governor to carburetor for that matter? Or do I need to look at some other issue?

If it is the throttle moving back a bit yet(I think that is what you are saying) I'd try tightening the spring a bit more. It should stay in place in all positions. Another trick can be to put a bit of sand or iron filings in between the disks. Probably doesn't help the long term life of the disks, but does work.

Aren't there some dowel pins in that handle ? Were yours worn ? For some reason I'm thinking something like that in there holds or actuates the plate in there and if worn bad can give too much play in the friction part ?

There is a hollow bushing that goes over the adjusting bolt and two dowel pins pressed into the cast handle. The pins and bushing should be polished up where the rear plate slides on them. This is a good place to use never-seize.

My reply is hopefully going to all 3 of the responses I have had. All 3 of your suggestions have been great. To coonie Minnie, I will say that I have tightened up the spring a little bit at your suggestion, and I believe that is going to help. We are having blowing and drifting snow where I live right now, and so I do not want to open up my shop door to lose heat. So I will give that a try. To Mike M, I will say that those dowels could be wore enough to give just a little bit more 'slop' than what should be. What about the holes in the handle? If I put new dowels in, will I only fix it half way, or do the dowels take most of the wear because they are not cast iron like the handle? To ET, I will say that the bushing did show some wear in the middle. It appeared to have a small groove wore around the bushing. So here is my question to all of you; what's there to lose besides a few dollars, to order a bushing and some dowel pins? It surely can not hurt. If I can not order them, a machine shop should surely be able to make a pin that works, and I should be able to find the right diameter tubing to cut off the right length to make the bushing. Thank you all!

It has been so long since I have had one apart I'm not sure what operates what in there ? But I seem to think that there is something in there besides the friction disc plate that gets worn giving lost motion. And I sure would wait until you can be down without fear of needing the tractor.

I took an old boot and cut the disc out of it 15 yrs ago and still going strong.

The key to having the friction disc work properly is for the inner plate to float freely on the bushing and dowel pins before you tighten the spring. New dowels and bushing wouldn't hurt a thing.