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1948 John Deere A rough running


 
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wlmccabe
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PostPosted: Wed Jun 22, 2022 6:34 am    Post subject: 1948 John Deere A rough running Reply to specific post Reply with quote

JD A was running good but became hard to start. When I got it started it runs rough and pops very loudly through the exhaust system. I'm not sure where to start. I tried carburetor adjustments but it doesn't seem to change anything. Anyone have experience with this problem? I appreciate any help/advice that can be given.
Thanks,
WL McCabe
 
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greenmech
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PostPosted: Wed Jun 22, 2022 6:52 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

I would start by cleaning the carb real good. Ron MN
 
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rustred
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PostPosted: Wed Jun 22, 2022 7:24 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

check your compression and valve lash settings also. can be a burnt valve. a carburator will not cause a popping.
 
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Dan in Ohio
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PostPosted: Wed Jun 22, 2022 9:05 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

WL,
Leave your carb alone unless you have the needed drill bits and experience to do the job correctly, you may cause more problems and expense, just a soak job is not a cleaning for your carb. A year or so ago my 60 (best running most reliable tractor I have) started acting like it was running out of gas. Upon adding more gas if it would start it would cough, snort and pop like it still had a fuel related problem.

Long story short and many frustrating hours later I found the condenser had failed. At less than $12 each I now keep two Blue Streak DR60 condensers from Oreilley's on hand.
 
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David from Kansas
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PostPosted: Wed Jun 22, 2022 11:41 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

Had a '51 AR do that a few years ago. Tried everything. Finally started changing condensers in distributer and finally started and run like it should. Has been OK since. Does your A have a distributer? If so, that is where I would start.
 
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Bob Harvey
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PostPosted: Wed Jun 22, 2022 2:00 pm    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

I agree. Most likely distributor problem (if it has one). Another common problem is corrosion in the cap and rotor. Luck !
 
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ET
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PostPosted: Wed Jun 22, 2022 2:46 pm    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

Did you try a fresh set of spark plugs
 
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rustred
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PostPosted: Wed Jun 22, 2022 5:17 pm    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

well he said popping out the exhaust pipe. that is not weak spark , it is valves and or timing. check compression first.
 
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ET
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PostPosted: Thu Jun 23, 2022 2:23 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

Unburned fuel from lack of ignition passes into the hot exaust manifold and ignites there causes the popping out the exaust.
 
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Mike(NEOhio)
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PostPosted: Thu Jun 23, 2022 4:18 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

They will backfire if the fuel mixture is too lean. Try opening the load jet a little at a time first.
 
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rustred
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PostPosted: Thu Jun 23, 2022 5:18 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

i said to check compression, that way a person knows if its running on one cyl. or two cyl's. then go from there. you need a starting point instead of guessing. still saying if its popping or backfiring out the exhaust and running on one cyl. you have valve problems. pull a plug wire of from each side one at a time. if it keeps running on one cyl. compression would be ok. if it stops with one wire off its as i said.
 
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Dan in Ohio
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PostPosted: Thu Jun 23, 2022 9:13 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

rustred,

Thanks for mentioning compression and not running on one cylinder. I recently tried to get my gas 70 to run as well as my 60 which is the smoothest running tractor I have. I followed the OM and tried to adjust the carb and that required getting it to run on one cylinder, no matter what I did it would not run on one cylinder. Now I know why that happened, although this tractor seems to have decent power but certainly not like my 70 diesels have.
 
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fixerupper
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PostPosted: Thu Jun 23, 2022 6:25 pm    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

Mag or battery ignition? If it has battery ignition it sure sounds like a bad condenser. I am far from an expert on mags so I dont know if a bad condenser in a mag acts the same as a bad condenser in a battery ignition. When the engine is running the condenser will short out the spark for a couple revolutions, then it will start sparking again and the built up gas fumes in the muffler goes bang. It gets your attention.
 
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Steven Allen
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PostPosted: Fri Jun 24, 2022 5:23 am    Post subject: Re: 1948 John Deere A rough running Reply to specific post Reply with quote

fixerupper wrote:
(quoted from post at 22:25:06 06/23/22) I dont know if a bad condenser in a mag acts the same as a bad condenser in a battery ignition.


I'm no expert, either, but, in my experience, a bad condenser in a mag can have the same effect.
 
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