1951 John Deere B with a jd 50 power block

   / 1951 John Deere B with a jd 50 power block
  • Thread Starter
#11  
Alright tryed adjusting the carb. Still ran the same. But noticed that you are correct about the 1/4 throttle shut down. So that will be next. Check the main jet. Now this carb came came off a running 60 but I guess we coulda sucked something up. Thank you for your inputs. It's greatly appreciated!
 
   / 1951 John Deere B with a jd 50 power block #12  
Daveb50 said:
Alright tryed adjusting the carb. Still ran the same. But noticed that you are correct about the 1/4 throttle shut down. So that will be next. Check the main jet. Now this carb came came off a running 60 but I guess we coulda sucked something up. Thank you for your inputs. It's greatly appreciated!
Click to expand...

Is there any crud in the tank that could have found it"s way into the jet.
 
   / 1951 John Deere B with a jd 50 power block #13  
Daveb50 said:
So you think it has to much air? The spark plugs are black sewty looking
Click to expand...

That makes a difference. You didn't mention sooty plugs initially.
Running 3116 autolites and solid core wires? Coolant temps 180-195F. The only problem could be shorting out plugs due to fouling , caused by incomplete combustion.
What fuel octane and timing to compensate for the power-bloc's much higher compression.
 
   / 1951 John Deere B with a jd 50 power block
  • Thread Starter
#14  
We are jus running regular fuel 87 octane and ignition timing has been moved forward and back and there's no difference
 
   / 1951 John Deere B with a jd 50 power block
  • Thread Starter
#15  
The tank was completely cleaned out
 
   / 1951 John Deere B with a jd 50 power block #16  
you need to trace the problems and work on them.

black sooty plugs will either be too much fuel, or incomplete combustion from weak spark... or a vacume leak causing you to need too much choke or extra fuel to keep the mix rich enough to run. I could see a flood condition causing this, and make her fall on her face when given the order for more butterfly from the gov..
 
   / 1951 John Deere B with a jd 50 power block
  • Thread Starter
#17  
Ok so not sure how I'm not tracing or working on them. So tonight we will start with a hotter champion b23 plug with our fuel air mixture set at 1 1/4 turns and see how it works. Last night we had it back firing thru the carb. She runs at idle jus fine until you give the butterfly a turn near 1/4 throttle and then she falls off and the plug near the fly wheel is really bad soot and the other is black but not as bad
 
   / 1951 John Deere B with a jd 50 power block #18  
just for kicks.. have you comp tested her?

bad valves COULD possibly cause some of this...
 
   / 1951 John Deere B with a jd 50 power block
  • Thread Starter
#19  
What's comp ratio of a 50 power block? And has all new valves and springs in it
 
   / 1951 John Deere B with a jd 50 power block
  • Thread Starter
#20  
And we had the valve cover off last night and checked the rocker arms for the required gap and it checked out fine.
 
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