WC only runs right with choke partially on
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=135915
Printed Date: 17 May 2025 at 3:56am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: WC only runs right with choke partially on
Posted By: eversr007
Subject: WC only runs right with choke partially on
Date Posted: 07 Mar 2017 at 8:56am
| Hi wondering if any one could help us with a problem that has been going on for a year or so. So here is the story. Dad has a 36 WC that my grandpa had and the engine block had a crack in it and one day it finally quit. We use it all the time. So we got a different engine out of another tractor and put a total overhaul kit in it. After doing so it ran great but had to always have choke on partially to get it to run good. So I checked for any air leaks. Then thought might be head. So we had the head redone at a machine shop and everything pressure tested. Still the same problem. I got busy and dad took to another guy that is good with tractors. He tried everything even put a different carb on it and still no change. The only thing that would be different that wasn't on the old engine was the manifold. We put a WD 45 Manifold on it. So could the air flow on that manifold not be enough with the smaller engine.? Or do you all have any thoughts. Thanks |
Replies:
Posted By: DrAllis
Date Posted: 07 Mar 2017 at 9:08am
| Open up the main jet on carb one full turn or more. |
Posted By: eversr007
Date Posted: 07 Mar 2017 at 9:19am
| Ok I will try that, but we tried adjusting it and nothing seemed to help. I've never had trouble adjusting usually but I'm no pro with carbs. So when we got carb adjusted where it would run right without choke on, It would spit and cough when pulled hard or run wide open. |
Posted By: DON G
Date Posted: 07 Mar 2017 at 9:38am
 Is gas going to carb? Maybe screen plugged.
|
Posted By: dt1050
Date Posted: 07 Mar 2017 at 9:40am
|
sounds like the float is sticking or not getting enough fuel ------------- Just cause it's orange don't make it a tractor, there's only one..Allis Chalmers |
Posted By: DougS
Date Posted: 07 Mar 2017 at 9:44am
| Intake manifold may have a leak. |
Posted By: Steve in NJ
Date Posted: 07 Mar 2017 at 12:32pm
|
Sounds to me like a lean condition. Intake vacuum leak. Pinhole or crack somewhere possibly. Engine may need a fatter mix under load if idle and off-idle are good at the Carburetor and under load is a problem. Fuel delivery problem to Carb... HTH 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: CrestonM
Date Posted: 07 Mar 2017 at 12:43pm
Spot on!
|
Steve in NJ wrote:Posted By: shameless (ne)
Date Posted: 07 Mar 2017 at 12:47pm
| dad's old jd 3020....you had to do the same thing! dealer couldn't figger it out! the dude is sold that POS to asked me about it too....guess he still has to have the choke part way out. |
Posted By: alan-nj
Date Posted: 07 Mar 2017 at 2:15pm
|
I'm currently having the same problem with a wd45. Also had the head redone. Have 2 situations...carb and lower manifold ice up, so I put a thermostat in, idle for about 5 minutes until manifold heats up and ice goes away --- but then will still only run with choke half closed. I've gone thru the usual, including 3 different carbs and 2 different manifolds; drained tank, pulled bowl assembly, new fuel line....still stumped. I've let it sit for about a month now, will have to get back into it soon. ------------- If ignorance is bliss, than happy days are here again. |
Posted By: Gerald J.
Date Posted: 07 Mar 2017 at 3:24pm
|
I have posted 17 times in the past 7 years on this forum about tuning carburetors and making engines run. The vintage carburetors are not factory tuned, they were tuned for each engine. intake manifold leaks can make partial choking necessary as can poor fuel supply to the carburetor, low float bowl level from improper float setting or fuel flow restrictions. One of my longer posts is in the thread at: http://www.allischalmers.com/forum/forum_posts.asp?TID=90078&KW=carburetor+tune&PID=713218&title=update-on-my-rough-running-wd-again#713218" rel="nofollow - http://www.allischalmers.com/forum/forum_posts.asp?TID=90078&KW=carburetor+tune&PID=713218&title=update-on-my-rough-running-wd-again#713218 For more search this forum for the keywords carburetor tune posted by me for the last year and before with the advanced search. Gerald J. |
Posted By: eversr007
Date Posted: 29 Apr 2017 at 12:05am
| So dad was using the wc and it quit running one day. So we put a new coil, condenser, filed the points, new rotor , cap, plugs and plug wires . That got it running again but still had to have choke on a little but maybe a little better. tried to adjust carb and no adjustment did anything to how it ran other than when main jet was screwed all the way into seat. Took carb apart and cleaned every jet with wire and blew everything out. Put it back together and ran almost perfect without the choke on. But when you put it under a load it starts to stall a little. But no matter what you do with the top adjustment for the air mixture it doesn't do anything. You can take it all the way out and doesn't do anything. Bottom screw only changes engine when it is screwed all the way into the seat. But no matter how far you screw it out it never runs rich. Also put new needle valve and seat in. Plus new float. Any ideas??? One place told me to toss the carb and put one off a wd on it. I think the one on it now is a Zenith 7078. Also sprayed starting fluid on intake and carb and it had no change in sound. Has me stumped. |
Posted By: dawntreader74
Date Posted: 29 Apr 2017 at 3:11pm
| may haft to take the bowl mount out of the tank' an take it apart an clean it out' may have some crap down in there. blow it out with some air;; |
Posted By: JW in MO
Date Posted: 29 Apr 2017 at 6:13pm
|
Do you happen to have a filter between the tank and carb.? ------------- Maximum use of available resources! |
Posted By: Gerald J.
Date Posted: 29 Apr 2017 at 8:08pm
|
To adjust the carburetor jets for fastest running, you have to defeat the governor. Hold the throttle closed against the idle speed adjust screw and adjust the idle mixture for fastest running. Hold the throttle in a fixed position with the engine running 1600 to 2000 RPM and adjust the high speed jet for maximum speed.Might require unhooking the governor linkage. Otherwise the governor will hide any effects of the jet settings. The two adjustments interact so the sequence needs to be repeated several times. Another thing to check is the centrifugal advance mechanism in the distributor. If its not working right due to rust or broken springs the engine won't run well at all speeds. it takes advance as the engine runs faster to allow for the finite time for combustion to take place. Gerald J. |
Posted By: Steve in NJ
Date Posted: 30 Apr 2017 at 10:16am
|
If your not getting any change with adjusting the enrichment jet, there's a blockage or a problem (crack) somewhere deep in that Carburetor. The upper air/fuel mix screw is basically just for idle. The lower adjusting jet is for enrichment under load. (working) If you crank that enrichment screw out at full throttle you should start to see a tinge of black smoke from the stack. After reinstalling your Carburetor and seeing how the engine ran much better with almost no choke, showed your cleaning method helped. These Carburetors can really get some dirt and debris jammed in their enrichment and idle circuits. Being I rebuild a lot of these Carburetors, I can't stress enough about making sure the fuel tanks are spotless, along with the fuel delivery systems. It doesn't take much for these Carbs to get messed up. The 7078 especially, being it was a dual fuel Carburetor to start off with. Distillate fuel wasn't the cleanest.... 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: BrianC
Date Posted: 30 Apr 2017 at 11:14am
|
A long shot, but check that you don't have diesel mixed with your gas. |