Ford 8N Carb Problem

   / Ford 8N Carb Problem #1  

stevegintn

New member
Joined
Sep 18, 2008
Messages
6
Location
Shelby County, TN
Tractor
'48 Ford 8N
My '49(?) Ford 8N tractor (front distributor) quit on me, and I saw that gas was running out of the bottom of the carb lower body. Closer inspection revealed a recessed screw had fallen out. I removed the lower body, and reinstalled with a temporary plug, but now misses badly. Can anyone tell me what that part is? - either it was not simply a drain plug, or I reassembled something wrong.

I've attached a picture showing where the missing screw is (see arrow).

Apprec any help!

SteveG in TN
 

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   / Ford 8N Carb Problem #4  
Once upon a time it was a brass plug filter - similar to the old brass fuel filters used in GM (Rochester) carbs. It is merely a vent for the throat of the carb, to let any liquids drain out but not allow dirt into the throat area. Will not affect the operation of the carb but will allow unfiltered air into the intake if not plugged. If there was a screw in there, a rebuilder must have installed it. Marvel Schebler carbs. are notorious for floats going bad and taking on gas, shake the float to see if this has happened. Also the seat of the needle & seat assembly may have loosened and started backing out. The float can be roughly adjusted if you turn the carb upside down and the float should be very close to parallel to the airhorn gasket surface, gasket in place. If you have the actual spec., use a drill bit of the proper size as a gauge to measure from the top of the float to the gasket surface. Float drop is important too, the float can potentially hang open if it drops too far, can't remember what that spec is, I think around 1 9/16" or so. The large plug underneath is a drain for the main jet well - debris collects here first and will cause serious running problems. The main jet can be removed with this plug out but be sure you have the exact size screwdriver for the jet and be careful - it is brass and easily broken. The small adjusting screw on the carb is the idle mixture - adjust it with the engine at low idle. The large screw adjusts the power circuit mixture, adjust it at operating rpms and normal engine temp. Good luck.
 
   / Ford 8N Carb Problem
  • Thread Starter
#5  
Thanks again, guys! - Skip, I posted to the N-forum, and there was given the John Deere cross-ref part number (75-98) for a replacement 'strainer', as it's called.

Called my local JD dealer, and they'll have me one in the morning (cost ~$6).

I may try my luck and screw it in, see how she runs ... if no luck, it's remove, disassemble, clean, and readjust. if that doesn't help, guess a new carb?
 
   / Ford 8N Carb Problem
  • Thread Starter
#6  
OK, I got my $6 part at the JD dealer yesterday.

But one more question: it's a simple little 'strainer' plug, i.e. not any kind of 'screw' or bolt (no threads). However, the hole in the bowl it came out of is threaded.

Does it just pop in? - if so, will it stay?

Going out in a minute and remove the whole carb, to get a better look.
 
   / Ford 8N Carb Problem #7  
i found a 49 8n this past week has water coming out the exhaust and rear lift is weak other wise tractor is clean owner may sell since i now mow his pasture he said he might sell for 1500$
 
   / Ford 8N Carb Problem #8  
OK, I got my $6 part at the JD dealer yesterday.

But one more question: it's a simple little 'strainer' plug, i.e. not any kind of 'screw' or bolt (no threads). However, the hole in the bowl it came out of is threaded.

Does it just pop in? - if so, will it stay?

Going out in a minute and remove the whole carb, to get a better look.



They must have gotten you the wrong part. I would take the carb to them & show them the part you need. There may have been different bowls for that carb. meaning 2 different parts. I had a carb like that on a fegurson that I onced owned. Cleaned it several times . but , I don't remember seeing that part
 
   / Ford 8N Carb Problem
  • Thread Starter
#9  
They must have gotten you the wrong part. I would take the carb to them & show them the part you need. There may have been different bowls for that carb. meaning 2 different parts. I had a carb like that on a fegurson that I onced owned. Cleaned it several times . but , I don't remember seeing that part

Nope, Ken, it's what I needed - I was mistaken about the hole being threaded - you just tap the porous strainer 'plug' in to the hole and that seemed to do it ...

So I pulled the little carb and did that, went to put it back on, and as my luck goes, one of the carb studs broke when I was tightening it.

So pulled it off again, drilled out the broken stud, and luckily, AutoZone had a set of (water pump) studs the same size.

Put it back on again with new stud, fired it up and it ran great for about 5 minutes. Cut it off, but now it won't start. :(

Back to the drawing board! :confused:
 
   / Ford 8N Carb Problem
  • Thread Starter
#10  
Well, maybe I'm an Idiot? - went back last evening and it started and ran fine - maybe I had the key off?

Thanks again for all the help!
 
   / Ford 8N Carb Problem #11  
Steve..The entire time it was probably a bit of grit in the seat of the float needle holding the float valve open.. letting her flood.

soundguy
 
   / Ford 8N Carb Problem #12  
i found a 49 8n this past week has water coming out the exhaust and rear lift is weak other wise tractor is clean owner may sell since i now mow his pasture he said he might sell for 1500$

If you have water out the exhaust.. check the oil to see if there is any water in the oil.. and check the radiator for lots of oil init. a little oily sheen is ok.

Sometimes a wet stud will leak.. and if so, you can pull it, pucky it, and reinstall.

1500$ is good privce for a running N.. but I would not want to buy one with a cracked block.. etc.

Weak lift?.. could be excessive leaks.. or weak relief.... open the dipstick inspection port and lift a heavy load.. look in with flashlight and look for leaks up top.

Bottom line.. to completely R&R the 3pt lift with new gaskets and a ne wlift cyl and piston is about 200$.. with no cyl.. and just hone the old one.. about 100$.. should take about 8-9hours for a lift cover and pump rebuild as long as no parts in the pump other than the screw in relief valve need to be repalced.

get an I&T FO-4 service manual if you plan on doing this... EZ job more or less.. lift cover and pump each weight about 50#...

soundguy
 
   / Ford 8N Carb Problem #14  
post back if you need any help on the hyds.

soundguy
 

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