Firing problem
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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=161564
Printed Date: 08 Jun 2025 at 5:21pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Firing problem
Posted By: spencefarm
Subject: Firing problem
Date Posted: 03 Jun 2019 at 10:14am
| I've got spark, compression, and fuel. Why can't I get it to fire? |
Replies:
Posted By: HoughMade
Date Posted: 03 Jun 2019 at 10:19am
|
Timing? Too much fuel? ------------- 1951 B |
Posted By: spencefarm
Date Posted: 03 Jun 2019 at 10:20am
| It ran no problem before. Could timing have been knocked out with it just sitting here? |
Posted By: HoughMade
Date Posted: 03 Jun 2019 at 10:28am
|
Generally, no. How have you tested for spark and fuel? ------------- 1951 B |
Posted By: Dick L
Date Posted: 03 Jun 2019 at 10:29am
Probly not but it is only things to check so it can be rule out. I just had a no start and was not getting spark at the plugs with power at the points. Put new coil and condenser and still no spark at the plugs. a new distributor cap last spring. I wiped it out when changing the coil how ever on close inspection it had a green build up. I scraped it off and it fired right up. |
spencefarm wrote:Posted By: spencefarm
Date Posted: 03 Jun 2019 at 10:31am
| I have a little inline spark tester that I used to check for spark. And the carburetor is getting flooded trying to crank it for too long. |
Posted By: spencefarm
Date Posted: 03 Jun 2019 at 10:31am
| How best should I check the timing? |
Posted By: Dick L
Date Posted: 03 Jun 2019 at 10:43am
Cold, non running or static timing on any four cycle engine is timed at TDC on the compression stroke at number one cylinder. Depending on what engine, you look for the TDC on the flywheel where the inspection hole is located. At that point if it has a distributor the rotor would need to be pointed to the number one wire terminal with the points (just)ready to open. On a magneto the impulse will snap just past TDC. |
Posted By: HoughMade
Date Posted: 03 Jun 2019 at 10:48am
|
Were it me, before I got too deep with the timing, I would widen out the gap on the inline tester (if it is one that will do that) and see if it will jump more than 1/8th (.125) of an inch. If yours doesn't allow for adjustment the gap length, then put a length of wire in the coil wire or on a spark plug wire and see if it will jump that gap. Sometimes some spark isn't enough spark, but if it will jump the 1/8th inch gap, weak spark probably isn't the problem.
Though I would add that a really good spark will jump over 1/4". ------------- 1951 B |
Posted By: OldSchoolRecovery
Date Posted: 03 Jun 2019 at 11:00am
| Put new plugs in before messing with the timing. Then, a little starting fluid to make sure you don't have a fuel issue. Then you have ruled two things out. Then a compression check. All within 10%, number dosen't matter. Then , maybe look at timing. |
Posted By: DougS
Date Posted: 03 Jun 2019 at 11:20am
|
A spark at atmospheric pressure doesn't mean you will have a spark at 100 psi. I doubt it's the timing if it ran when you parked it. It could be moisture, wires, plugs. Cranking the engine shouldn't cause the carburetor to flood unless you are cranking it with the choke closed. |
Posted By: frnkeore
Date Posted: 03 Jun 2019 at 11:35am
|
Timing would be the last thing that wouldn't allow it to fire and run, if it is at all close. Regarding timing, I do it a little different but, it's a very accurate way of setting timing. When #1 is coming up on the compression stroke, stop the flywheel at the timing mark that the book or you want for timing. Set the point gap, to your specs, then put one of the ohmmeter wires to the points and ground the other side. You then twist the distributor until the ohmmeter indicates a open circuit (points break) and lock the distributor down. You then have the exact timing, if the bushing in the distributor are good. You do it the same way with a mag. You can also use this system for checking total timing turn the flywheel to the total timing mark you want, then twist the rotor shaft, to advance the centrifugal weights and the ohmmeter should show a circuit break, if not, hold the advance and again twist the distributor until it breaks. I do the total advance and ignore the initial advance. ------------- Frank 1959 D17 Series I #24001+, '59 D14 '55 & '59 Ford 850 & 861 Ferguson TO 35 Deluxe, Oliver 70 and 5 more. |
Posted By: Steve in NJ
Date Posted: 03 Jun 2019 at 11:38am
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I'm wit' Old School there. Toss a set of plugs in it. (not champion, somebody elses) It'll probably fire right up. If it ran fine when last used, the timing isn't gonna change. I would think, its a oxidized set of points or an old set of plugs or both.... mailto:Steve@B&B" rel="nofollow - Steve@B&B ------------- 39'RC, 43'WC, 48'B, 49'G, 50'WF, 65 Big 10, 67'B-110, 75'716H, 2-620's, & a Motorhead wife |
Posted By: JaredC(WI)
Date Posted: 03 Jun 2019 at 11:44am
|
Charge the battery and then try. My CA does just what you are describing even down to the flooding carb. Seems like a partially discharged battery will have enough juice to start turning over, sucking fuel, etc but not enough umpf to ignite the fuel. |
Posted By: Lonn
Date Posted: 05 Jun 2019 at 12:36pm
|
What are we working on? I had a lawnmower once that the plug wouldn't give a spark under compression. New plug solved that after a lot of head scratching..... and help from an older experienced mechanic.................... Once I had a lawnmower that would act like it was flooding out after it got warmed up. Turned out a new key switch solved that because as the old switch heated up it built up resistance and then was losing ignition. Funny things can happen if when you think you have fuel, spark, and compression. ------------- -- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... - Wink I am a Russian Bot |