Question on warming up a tractor

45er · Jul 26, 2005

I have a NH 1925 tractor. My normal routine is to start the tractor and let it idle for 5-10 minutes before use. The last two times I've started off shredding with the tractor, when I rev it to 540 rpm and start to shred, the engine automatically drops off 540 to a lesser idle speed. I push it back to 540, and it drops off again. This happens for 5-10 minutes and finally it will stay in the "green" operating rpm range. Is this a safety feature such that the engine will not operate until it is fully warmed up or is there something else going on? Thanks. Rob

jinman · Jul 26, 2005

Sounds to me like your throttle's friction pad is not adjusted tight enough. I suspect it may be worn slightly due to being in the operating range most of the time. It probably drops back slightly when you push it up with the engine cold. When the engine heats up it takes a little less fuel to produce the same rpm, so it seems like the throttle is not moving when it is actually in the same position.

The throttle friction disc is adjustable on my TC45D and is also probably adjustable on your 1920, but I don't know enough specific info to give you advice on the adjustment.

SteveInMD · Jul 26, 2005

I agree. There is something else going on - I don't think it's a safety feature. The best way to warm up a diesel is to put a light load on it (like drive it around), not just let it idle. This is especially true when it's cold out.

45er · Jul 26, 2005

Thank you both for your replies. I will check the throttle friction pad and see if it is adjustable. Good idea on the idling too. I'll change my habits there. One thing's for sure though, it wasn't "cold" in Bellville, Texas Sunday. It was 96 degrees and felt like 196! Because of thoughtful replies by guys like you, this post has become invaluable to this "newbie" tractor owner. Thanks again for taking your time to respond.

RedRocker · Jul 27, 2005

Yeah, cold isn't a real problem right now in Texas. /forums/images/graemlins/grin.gif

Soundguy · Jul 28, 2005

I agree.. check the throttle friction pad.. I just had to tighten mine on my Nh 7610s. It would slip a bit and let the tractor run a tad less than 540.. I got in the habbit of resting my foot on the foot accel pedal to overide this.. but finally fixed it by tightening the adjustment on the disc.. etc.

Soundguy

OffBalance · Jul 30, 2005

I had trouble with the tach showing the idle dropping off on my new TC24, but it did not sound like the engine was dropping RPMs.

I finally realized that the alternator belt was loose. I figured that is how they get the RPM for the tach. I Tightened her up, and no more low RPMs!

thcri · Jul 30, 2005

MY TC29D I have had to tighten the throttle friction pad twice in three years. Exact same scenario as you. That is were I would be checking.

murph

45er · Aug 1, 2005

After reading your help on this, I called a NH dealer and asked him if there was anything in the manual on tightening the friction pad (the manual is with my tractor 50 miles away). He said "no", but also said that I should be able to look "up under" the dash and see the bolt. He didn't think I'd have to dismantle the dash to get a wrench to it. Well, I went to my place Friday and looked at the tractor. Yep, looking through a seam in the dash, you could see the bolt right down the throttle lever about 8 inches just like he said, but darned if there was ANY way to get a wrench to the bolt. For you folks who have tightened the bolt before, did you have to remove one of the dash panels to get to it? On my NH 1925, it looks like you have to remove the ignition key and kill button assemblies, then unbolt the right side of the dash to remove a panel. If there's an easier way, I'd sure like to know about it. Thank you very much. Rob

Soundguy · Aug 2, 2005

I was able to use a small wrench, and snake my hand under the dash, and fidget with it onmy NH 7610s... not ideal.. but worked for me without removing the dash. Course that's a different tractor than you have too.. good luck..

Soundguy