Bad running D17
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=183599
Printed Date: 22 Aug 2025 at 1:09am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Bad running D17
Posted By: NDBirdman
Subject: Bad running D17
Date Posted: 01 Oct 2021 at 3:18pm
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Question for the D-17 mechanics. When cold, runs like a top, starts very easy and purrs like a kitten. Get her hot and forget it. Going down the road, starts spitting/sputtering. I'm told she has done this for a while. Let it cool, starts/runs like a new engine. Was told engine was rebuilt before my friend bought it. It did it on way home last night bad. I ran to shop, grabbed a new coil/condenser, ran back down road. Started her up, still doing it so we did a quick coil change, no fix. Changed out condenser, no fix. Limped her back to shop and started pulling plug wires to see which cylinder was the culprit. 1 and 2, firing good. #3, dead to the world. For SnGs, pulled wire off #4, dead to the world. So, when hot, 1 and 2 fires, 3 and 4 nothing. Said eff it, time for a beer or 2. Bout an hour later, started up to move into shop, darn thing ran like a top/idled great. Full throttle, sounds great now. If it was fuel, would do it all the time, cold or hot. What am I'm missing? ------------- 1955 WD45 S#205467, 190XT #6652 DXT |
Replies:
Posted By: plummerscarin
Date Posted: 01 Oct 2021 at 3:53pm
| Swap the plug wires for SnGs |
Posted By: Stan R
Date Posted: 01 Oct 2021 at 3:59pm
| Solid ignition wires are recommended I believe. Could be that. |
Posted By: Boss Man
Date Posted: 01 Oct 2021 at 4:02pm
| Check the advancement weights in the distributor. Had a Case that did that and advancement mechanism was seized. |
Posted By: WF owner
Date Posted: 01 Oct 2021 at 5:10pm
| If you are running Champion spark plugs, that would be the first thing I would suspect. |
Posted By: WIAllisFan
Date Posted: 01 Oct 2021 at 5:44pm
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Got a D19 that is basically doing the same thing. You can check out my thread https://www.allischalmers.com/forum/d19-troubleshooting_topic183561.html" rel="nofollow - https://www.allischalmers.com/forum/d19-troubleshooting_topic183561.html I found that there is no ballast resister for a coil that requires an external resister, so I'm putting one in over the weekend, hopefully that does it. If that doesn't work I'll do a condenser and points, and if that doesn't do it.....well I'll post here again cause I'll be out of ideas.
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Posted By: steve(ill)
Date Posted: 01 Oct 2021 at 6:09pm
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crack in cap between #3 and #4 ? Change cap and wires...... and new plugs cant hurt.
you should be using a 12 v coil.. NO RESISTOR needed... Dont use a 6v coil with external resistor on a 12 volt system.. bad design. ------------- Like them all, but love the "B"s. |
Posted By: DaveKamp
Date Posted: 02 Oct 2021 at 4:40pm
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If it's firing well on 1&2, but not on 3&4, that suggests to me that the source of spark is NOT the culprit. Plug wires are NOT going to be a 'no fire' issue, but use solid core wires on magnetos... battery-coil systems use resistor coils or plugs to suppress high frequency oscillations that will shorten the life of the condenser, points, and the machine operator (if his wife's football game is being interfered with by all that ignition noise) Locating the spark is the issue. It COULD be the cap... but Here's what I think: I think that the points are not getting proper operation on the 3/4 cylinder. I'd be willing to bet that if you took off the cap and rotor, and grabbed that distributor shaft, and wiggle it around, it'll be sloppy in the bushing. I'll bet that if you pull that distributor out, and either 1) Drop in a known-good or 2) pull it apart, give it a serious rehab, with a new bushing, and possibly (if it's worn) grind the shaft to true, and undersize the bushing to match, and put it back together, it'll be MUCH happier. The OTHER possibility (and it could be in conjunction with the shaft bushing)... is that the POINT CAM is worn, and you're not getting sufficient lift. So you ask WHY would it do this when hot... but not cold? Well... because the OIL that's passing around all those gears is thick when it's cold... and once the oil is warm, it's thinner. Now, if neither of those prove out, then the next thing I'd do, is get it good and hot, so it's missing... shut it down, and give it a quick compression test on all four. IS it low on CR on those two? Either there's some valve clearances that need to be reset, OR there's a compression leak. If the oil and coolant are both clean, it's probably just between the cylinders. How would I determine wether it was an ignition, or a compression circumstance? I'd start it up, get it running good and warm, AFTERDARK. Once it starts missing on the back two, pop the plug wires off 3&4, and connect them to some spare plugs that're grounded to the side of the block somehow, and look-see if you've got spark on those two. If they're snappin-nasty-hot, then you're dealing with a compression circumstance, not an ignition circumstance. If the spark you see is flaccid, check the diz shaft and point cam. ONE OTHER THING... is the intake manifold. In order to provide sufficent carb heat for atomization, the intake and exhaust runners share a wall. When cold, this casting will likely be pretty tight, but once warm, if there's a slight crack buried in there, it'll start opening up, and eventually, you'll have enough of a leak, that the mixture on whichever side will lean-out, and you MIGHT even start to get some manifold backfire (if there's sufficient oxygen and fuel to do so)... but when you cool it off, it contracts and seals up again. Swapping the intake and carb with a known-good will prove that out. ------------- Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest. |
Posted By: WF owner
Date Posted: 03 Oct 2021 at 6:12am
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How did you determine which cylinders weren't firing? Did you remove the plugs and check for fire or did you short them out with a screwdriver while it was running? My D-17 Series 4 was doing the same thing a couple years ago. With it running #3 and #4 cylinder had no (actually intermittent) spark. When I removed the plugs, and turned it over, all cylinders were sparking. A new set of NGK plugs solved my problem.
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Posted By: NDBirdman
Date Posted: 03 Oct 2021 at 2:27pm
While running, we removed the plug wire from the plugs one at a time. When you remove one not firing(plug wire), the eng. will not show a difference. But, got to warn you, if you have a ... leaky boot/wire, you will instantly know you just grabbed a wild cat by the arse.. LOL ------------- 1955 WD45 S#205467, 190XT #6652 DXT |
WF owner wrote:Posted By: AC720Man
Date Posted: 03 Oct 2021 at 5:13pm
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Bird man I’m still laughing my arse off at your last comment!! Thank you I needed a good laugh. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: WF owner
Date Posted: 03 Oct 2021 at 8:01pm
If you got a shock, there is fire to the plug. I took a screwdriver and grounded them to the head. #3 and #4 were not firing. My problem was the former owner had put Champion plugs in it. I went to the local auto parts store and they didn't have Autolite plugs, so I got a set of NGK plugs. Changed the plugs and it instantly eliminated the skip.
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