AC 170 gas
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=208022
Printed Date: 08 Sep 2025 at 10:34am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: AC 170 gas
Posted By: Tracy Martin TN
Subject: AC 170 gas
Date Posted: 01 Sep 2025 at 7:02pm
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I noticed my gages did not read power today. Put a new battery in it, thought old one was bad, didn't seem to hold a charge. I wonder if my tractor is charging now. Gage doesn't show it.Has factory alternator with the regulator under battery. What is easy way to check this out? What is most likely fix? Thanks, Tracy ------------- No greater gift than healthy grandkids! |
Replies:
Posted By: BillinAlberta
Date Posted: 01 Sep 2025 at 7:22pm
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My quick and dirty first step is to get a reading on the voltage with engine stopped and with engine running.No change then pull alternator and take it to a parts store to check function. It has been the year of the crapped out charging systems for me.One of the D17's,the CA 6 volt genny and Big Al the gas passer(7020 gas) all needed work.
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Posted By: BigGuy1000
Date Posted: 01 Sep 2025 at 7:56pm
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First check to see if the regulator under the battery on the torque tube has a good ground, the resistance from the bottom mounting plate of the regulator to the tube must be much less than one ohm in order to regulate and charge properly! Some regulators had a short stranded wire to make this connection. Clean all! |
Posted By: only AC orange
Date Posted: 02 Sep 2025 at 7:32am
| To check if alternator is charging - place a screw driver or end wrench against the rear center of alt. while engine is running, if charging, screw driver or wrench will stick to end of alt. (magnetized). |
Posted By: Tracy Martin TN
Date Posted: 04 Sep 2025 at 12:16am
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Can't use screwdriver, tach cable is in the way. Does show discharge with lights on. Fuel gage will not turn on or off with key. Looks like one wire at regulator is grounded to tractor frame. What do I do next for simple test? Thanks, Tracy ------------- No greater gift than healthy grandkids! |
Posted By: TedN
Date Posted: 04 Sep 2025 at 1:06am
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With the fuel gauge also not working it sounds like you may have lost the accessory side of the key switch. It should send voltage to the "3" terminal on the regulator if I remember right, and that would be the next place I would check. You don't need to be precise about voltage for an initial test, it either has voltage or it doesn't. If not, you may have a bad key switch, a bad wire, or a bad protection device(fuse or circuit breaker). My experience has been with 190XTs, so I'm not 100% sure what you have in the 170. I have had a bad switch, and have had it be as simple as a wire not making good connection at the switch. If it does have voltage then you will need to look at field voltage on the alternator to see if the problem is there or the regulator(or somewhere in between). Probably not enough help to get it fixed but hopefully looking in the right direction. Ted ------------- 190XTD seriesIII, 190XTD seriesI, maroon belly 7000, 190XTD series??? project(or maybe parts) |
Posted By: DrAllis
Date Posted: 04 Sep 2025 at 6:21am
| From the 1960's local service schools on 170 thru 220 tractors electrical systems testing: If the system isn't charging, the first thing you do it verify the ammeter is functional by turning on the lights. If the needle dips, you can assume your ammeter is OK. Second step is to make (already have) a jumper wire to go from the "hot" post on the backside of the alternator into the square plug on the back of the alternator where the existing field wire is to excite the fields. A full 12 volts to that one (green?) wire will place the alternator into full output. If the alt charges now, you have a regulator or wiring/grounding issue. Wiring issues in those days didn't exist and maybe if the hood was removed sometimes the ground wire didn't get reconnected. If it doesn't charge, you have an alternator issue. OEM old school regulators make a "clicking" sound when you turn on/off the key. Modern regulators don't because there are no breaker points inside these days. |
Posted By: Tracy Martin TN
Date Posted: 04 Sep 2025 at 8:32pm
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Guys, i will give these a once over this weekend. Thanks for advice! Tracy ------------- No greater gift than healthy grandkids! |
Posted By: Tracy Martin TN
Date Posted: 07 Sep 2025 at 8:55pm
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I took a look at the 170 gasser today. I tried jumping the hot wire to the ground on back of alternator, no difference on ammeter gage. I did notice the only time ammeter gage moves is with the light switch on. No movement on fuel gage or water temp gage. How many wires should go to the back of key switch? Is there a good wiring diagram of the 170 gas ? I can't find one in my service manual, can't find my operators manual.I did get a half inch of much needed rain, need much more. Any help appreciated. Thanks Tracy ------------- No greater gift than healthy grandkids! |
Posted By: JoeM(GA)
Date Posted: 07 Sep 2025 at 10:55pm
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Tracy, check your email, couldn't get diagram to attach let me know if you need it larger ------------- Allis Express North Georgia 41 WC,48 UC Cane,7-G's, Ford 345C TLB |
Posted By: Tracy Martin TN
Date Posted: 07 Sep 2025 at 11:02pm
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Joe,I will check it. Thanks, Tracy ------------- No greater gift than healthy grandkids! |
Posted By: Tracy Martin TN
Date Posted: 07 Sep 2025 at 11:20pm
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I was wondering how many wires plugged to back of switch, looks like it had extra tabs not being used. Thanks, Tracy ------------- No greater gift than healthy grandkids! |
Posted By: JC-WI
Date Posted: 07 Sep 2025 at 11:23pm
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Tracy, here is a One-Eighty gasser diagram that is nearly identical to the One-Seventy to work for you.  As for the, "jumping the hot wire to the ground on back of alternator" Do not do that, unless you are expecting to see sparks when grounding it. Test to see if alternator is functionig good is as Doc said, take a jumper witr from alternator's charging post and touch the right post in the slip on connector, that should give you full output.. In your grounding of hot wire to ground, and had no spark, your wire may have a bad connection... or worse, broken /burnt wire. Did you try to hear the relay 'Click' "on" in the voltage regulator when you turned the key ON??? I have had a bad slip on connector that needed replacing after years of getting hot and rusted and finally not making connection. Also the regulators don't last forever either. I have had where the brushes were burnt off in the alternator and had to replace them and the slip rings too. Keep us posted on how your doing. ------------- He who says there is no evil has already deceived himself The truth is the truth, sugar coated or not. Trawler II says, "Remember that." |
Posted By: DiyDave
Date Posted: 08 Sep 2025 at 4:45am
A quick alternator test is to take a screwdriver and touch it to the back center plate or front of the rotating pulley while running. If the screwdriver is pulled magnetically toward that plate, or shaft center alt is good... https://youtube.com/shorts/t3n-wNJ8jvc?si=0oQ0a6MkUYl7Nu41" rel="nofollow - https://youtube.com/shorts/t3n-wNJ8jvc?si=0oQ0a6MkUYl7Nu41 ------------- Source: Babylon Bee. Sponsored by BRAWNDO, its got what you need! |
Posted By: DrAllis
Date Posted: 08 Sep 2025 at 7:55am
| The ammeter is wired hot all the time, key on or off. The ignition key has no effect on the ammeter. The regulator gets fired up by the ignition key which then sends a signal to the square plug on the backside of the alternator to begin charging. That's why the jumper wire test. Good ammeter and a short jumper wire will verify the alternator charging (or not). The other gauges on the instrument panel have nothing to do with any of the charging systems function. |
Posted By: Tracy Martin TN
Date Posted: 08 Sep 2025 at 9:50am
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DrAllis, I jumped the hot post on back of alternator to the square post unplugged to the little metal post inside of alternator. It sparked some but no charge on ammeter. Is that my only test option before checking anything else? Thanks, Tracy ------------- No greater gift than healthy grandkids! |
Posted By: DrAllis
Date Posted: 08 Sep 2025 at 10:03am
| Ammeter works because it shows a discharge when the lights are on. 12 volts applied to the square plug wire should have put the ammeter up to 20-30 amps depending on engine speed. 99% sure you have an alternator issue at a minimum. |