AC D17 Missing
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=139313
Printed Date: 29 Aug 2025 at 7:51pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: AC D17 Missing
Posted By: jmackin
Subject: AC D17 Missing
Date Posted: 11 Jun 2017 at 2:09pm
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Hello, I have an Allis Chalmers D17 series IV and am having trouble with it missing and back firing when it gets warm and I am putting a load on it. I can't figure out what the problem is. I have replaced filter air and cleaned out the fuel filter apparatus. I have also replaced most of the ignition timing parts but that did not seem to help. I have had the tractor for 20 years and it has run without issue. Can anyone give me any ideas on what to look for? Thanks. Jim |
Replies:
Posted By: DrAllis
Date Posted: 11 Jun 2017 at 3:24pm
| Bad spark plugs not gapped to .025" can cause a miss-fire under load--AC Delco 42 XL is my choice. An old ignition coil can act up when it gets warm. Spark plug wires that are not real wire can cause this. Ignition timing should be adjusted using a timing light with the engine at wide open throttle to F-25 or FIRE on the flywheel shining the light thru the one inch hole in the right side of the bell housing. Timing by "ear" isn't the right way to do it regardless of what they say at the coffee shop. Give the main jet on the carb one full turn out/open and see if that helps or does nothing. |
Posted By: Gerald J.
Date Posted: 11 Jun 2017 at 3:45pm
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Timing should change with engine speed, being sooner the faster the engine is running. If the centrifugal advance is stuck advanced (from broke springs or rust) it will backfire and not run good. Gerald J. |
Posted By: MACK
Date Posted: 11 Jun 2017 at 9:48pm
| New condensers are junk today. Try more than one before giving up on that being the problem. MACK |
Posted By: JohnCO
Date Posted: 12 Jun 2017 at 1:04am
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I thought someone had stolen it, easier to fix if you have it! ------------- "If at first you don't succeed, get a bigger hammer" Allis Express participant |
Posted By: Ted J
Date Posted: 12 Jun 2017 at 8:19am
------------- "Allis-Express" 19?? WC / 1941 C / 1952 CA / 1956 WD45 / 1957 WD45 / 1958 D-17 |
JohnCO wrote:Posted By: jmackin
Date Posted: 12 Jun 2017 at 9:40am
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DrAllis, I have not checked the timing. I will have to figure out how to do that now. Thanks for the response. Mack, not sure how to know if the new condenser I got is bad or not. Is there a way to tell or would you just get another one and try it? Gerald, I don't even know what a centrifugal advance is. I will have to do some research. Thanks for the response. JohnCO, not sure why I decided to confuse everyone with the last part of my post. It's not stolen. Honest. Take care. Jim |
Posted By: Gerald J.
Date Posted: 12 Jun 2017 at 5:18pm
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You need to find and study the operator's and maintenance manual and maybe the shop manual. I don't have them for the D17, but you might search at http://grandpastractor.com/forum/allis-chalmers-tractors" rel="nofollow - http://grandpastractor.com/forum/allis-chalmers-tractors Gerald J. |
Posted By: Ira
Date Posted: 12 Jun 2017 at 6:18pm
| A coil that has gone bad will display those symptoms. |
Posted By: Ted J
Date Posted: 13 Jun 2017 at 7:37am
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Jim, #1 you should NEVER change all the parts all at once when you are having a problem. The easiest and most needed changed is the plugs. Do that first and then check how it runs. Next, check the timing to see if it is good. Now change the condenser. Used to be easy doing this, because the new ones you bought were good! Made in the USA...... now all you get is junk from China at the box stores. Get one from NAPA or another car parts store. It doesn't guarantee that you get a good one, but your odds are better. How's it running? No change? Then change the points. Again, go to NAPA or order from Steve NJ (Barbato). Again, junk from China. After changing the points, you will need to re-do the timing. Got a timing light? Borrow one, or go to an auction. Get an old one, they are better than the junk you get now a days...... Remember, I'm doing this from the easiest to the hardest. Fix he simple things first and check how it does. Has always worked for me. Was me, I'd go with a new coil first and then the condenser. It's got all the symptoms of one of these is bad. One last thing to check is the valve clearance. That can make it run like you say too. HTH ------------- "Allis-Express" 19?? WC / 1941 C / 1952 CA / 1956 WD45 / 1957 WD45 / 1958 D-17 |
Posted By: Brian Jasper co. Ia
Date Posted: 13 Jun 2017 at 9:46am
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If I were going to buy points and condenser I'd be looking for Standard Blue Streak. Both of my gas tractors have Pertronix Ignitors in them. Check with Steve in NJ, I'm pretty sure he has them if you can't find them locally. ------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: Cal
Date Posted: 16 Jun 2017 at 6:54pm
| I would say if you have had it for 20 years and never adjusted the valves that is where I would start. A couple of tight valves will get tighter as the engine warms up. Adjusting valves often gets over looked in a tune up. Just my thought |
Posted By: JC-WI
Date Posted: 16 Jun 2017 at 8:14pm
Lot of good suggestions... What I was wondering, when did it start backfiring and missing? Before or after you started changing things... If it was missing first... did you check the spark plugs? how did they look? burning clean or had carbon on them... ? Carbon deposits in the wrong places in the engine will cause pre-ignition, knocking and possible back firing. Coil as mentioned can be a culprit, normally they fail when they get hot and quit at least that happened three times for me, no erratic misfire. Possible bad wires, make sure that you have solid wire not carbon core... even if you have resistor plugs. Check to see they are not leaking , crossfiring to other plug wires... Another possible is bad distributor cap, maybe moisture or carbon tracking or such, check for corrosion and burn inside on the contacts. Cheap caps seem to not last as long as the copper conductor cap... Rotor, that can cause problems too. Had one that the tractor would start missing under load and then one day it would only pop and bark....it finally got so bad that the problem was found to be grounding out to the dist. shaft. Points and condenser - They can cause different problems. Seems the old points are still better than the new points if you clean or 'dress up' the contacts and the old condensers were still good when they were changed out during a 'tune-up'... Today, not so the new foreign made condensers are junk as stated previously. Somebody found that out on the forum the other day. Maybe a wire feeding the coil or distributor going bad found one where some previous person had simply wrapped a wire around another wire and it would run till something made it not make contact and cool off and go again. the advance mechanism is under the point holder plate and you can see if they are working by taking hold of the rotor and see if it turns one way and springs back... But I can't see them causing problems your describing... Tho they may need a little TLC after all these years. Worn dist. shaft and bearings may be bad and allow shaft to slop around... Burnt intake valve can cause another problem as well as valve that isn't closing... Bad intake gasket can make the engine run really goofy too. Do you have clean fuel? Maybe water in the fuel? or maybe dumped some diesel in? Let us know what you find out that cures your problem. ------------- 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: Gogetter
Date Posted: 18 Jun 2017 at 1:59pm
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Moved |
Posted By: DonBC
Date Posted: 18 Jun 2017 at 5:34pm
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I also vote for a bad coil. A coil that is going bad will often be too hot to touch when the engine starts to miss. ------------- Jack of all trades, master of none |