200 tachometer
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=146324
Printed Date: 12 Sep 2025 at 5:16pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 200 tachometer
Posted By: acplowboy45
Subject: 200 tachometer
Date Posted: 10 Jan 2018 at 1:48pm
| I have replaced the alternator with the correct one I got from Sandy lake implement that has the tach drive on the back side of alternator. I just bought a new tach and when I start the tractor and I give it throttle the tach pegs out and not reading correct rpm. Is there something wrong. |
Replies:
Posted By: DrAllis
Date Posted: 10 Jan 2018 at 2:13pm
| When does it peg the tach ??? At half throttle ?? or very near the end of the throttle lever stroke?? Most tach's of that design I've been around usually peg the needle at100% full throttle. is it right ?? Not really, but it seems to be that way on a lot of them. Worn alternator pulley will make it worse. |
Posted By: acplowboy45
Date Posted: 10 Jan 2018 at 2:59pm
| It pegs there tach at 1/2 throttle. The pulleys are in good shape. |
Posted By: Lonn
Date Posted: 10 Jan 2018 at 3:07pm
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Is it one of those new Chinese ones? ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |
Posted By: Tim NH
Date Posted: 10 Jan 2018 at 5:41pm
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Did you put the original size pulley back on the alternator. ------------- 1950 WD 1959 D14 1955 WD45 1976 7000 B 207 |
Posted By: KJCHRIS
Date Posted: 10 Jan 2018 at 7:22pm
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F Y I, pulley on a 200 should be 3 1/8" diameter and using 1/2" wide belts. I'd bought a used alternator at salvage yard that had 3 1/2" pulley on it, tach did not read right. . ------------- AC 200, CAH, AC185D bareback, AC 180D bareback, D17 III, WF. D17 Blackbar grill, NF. D15 SFW. Case 1175 CAH, Bobcat 543B, |
Posted By: acplowboy45
Date Posted: 11 Jan 2018 at 1:20am
| Yes it has the correct pulley and belt on and yes it was a cheaper tachometer. The alternator is brand new. |
Posted By: LeonR2013
Date Posted: 11 Jan 2018 at 3:23am
| I'm sure you've already done it, but is all wiring in the right place? And are the grounds properly cleaned and tight? Is there a way to isolate the alt. and see what it is sending to the gauge? Let us know when you find the problem. |
Posted By: old farmer
Date Posted: 11 Jan 2018 at 7:04am
| I thought that tach was all mechanical and used cable from alt to tach head. Been awhile since I worked on one, like 30 plus years. |
Posted By: acplowboy45
Date Posted: 11 Jan 2018 at 12:06pm
| The tach drive is on the back side of the alternator. I did notice that the when I idle back the tach is slow to response. I'm starting to think that the problem is in the new tach. |
Posted By: acplowboy45
Date Posted: 24 Jan 2018 at 5:23pm
| I'm help me figure this out I spent the money and bought a lot more expensive tach from steiner tractor put it in...now the alternator drive on the back is correct came from Sandy lake implement brand new and the pulley measures 3 inch and guess what I give it throttle go to 3 on the throttle lines and the tach pegs out to 25 rpm. I'm puzzled...I have learned don't buy that cheap crap off ebay, you get what u pay for. |
Posted By: Oldoug
Date Posted: 24 Jan 2018 at 6:49pm
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Take your tach drive gear housing off your new alternator and make sure it has the correct drive gears in it. I think it's suppose to be 45 teeth on the larger gear and 12 on the smaller gear. Some have been put together with a 43 tooth gear and this will throw the RPM's off on the tach. ------------- Matt Folkers FOLKERS RESTORATION Restoring vintage things to last so the future can enjoy our past. |
Posted By: Oldoug
Date Posted: 24 Jan 2018 at 6:56pm
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Like Dr. Allis says also...you can't measure the tach RPM to throttle lever position like you're saying "3" on the throttle at 2500 RPM...is your engine running 2500 RPM with the tach reading 2500 RPM or is your engine running 1500 RPM with your tach reading 2500 RPM? ------------- Matt Folkers FOLKERS RESTORATION Restoring vintage things to last so the future can enjoy our past. |
Posted By: acplowboy45
Date Posted: 25 Jan 2018 at 3:16pm
| Ok I tore that back off the tach drive and the the big gear has 43 teeth and the small gear has 14 teeth. Where do I go from here. So I call Sandy lake implement and see if they will make it right or is that the way they come out now. Up for suggestions. |
Posted By: Oldoug
Date Posted: 25 Jan 2018 at 7:06pm
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You need to get the correct gears in there...they are available...it is up to you...you either purchase them yourself or call the place you got your incorrect parts from and explain what is going on and see what they will do. ------------- Matt Folkers FOLKERS RESTORATION Restoring vintage things to last so the future can enjoy our past. |
Posted By: ranger42
Date Posted: 27 Jan 2018 at 11:47am
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I went down this road with a 170 diesel. Bought a "new" tach from aftermarket source and did not register correctly. Thought about the gears, cable and all that stuff. Finally, I read an article on a guy who restores tachometers. His name is Haim Zeevi. He rebuilt these for a living and now is retired and does it part time. His work is excellent! He knows everything and I mean everything about tachometers. I called him explained what I had, and he said send it down and I'll have it done in 2 weeks. He even was able to put the hours I wanted back on the tach. I cannot say enough about the quality of his work He also rebuilds cables, gears, etc. He said that the new tachs are made with plastic gears and usually fail around 100 hours...so rebuild is a much better option. I received my tach back with a new cable and it looks and work flawlessly. His contact information is: Haim Zeevi 386-569-5284 |
Posted By: acplowboy45
Date Posted: 03 Feb 2018 at 12:06pm
| As a follow up let me say that Sandy lakes implement is a great place to do business with. I called about my tachometer problem with the wrong gears. I was called back they sent me the new gears I needed. This solved all my problems. |
Posted By: FREEDGUY
Date Posted: 03 Feb 2018 at 12:11pm
| How does the gear in the alternator get changed? Does it just slide in or is there more to it? I think our alt.guy got a small gear for a Massey(reads the wrong RPM'S). Thanks |
Posted By: ranger42
Date Posted: 03 Feb 2018 at 1:03pm
| the gear is threaded in the alternator. |
Posted By: orangereborn
Date Posted: 04 Feb 2018 at 12:54pm
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ranger42 wrote:Posted By: acplowboy45
Date Posted: 04 Feb 2018 at 4:53pm
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I got my tachometer at steiner tractor and so far it reads as it should so far. |