John Deere 730 gas

mfpd3

New User
I'm working on a john deere 730 gas. 2 years ago I parked the tractor because the water pump went out. I started it the other day and it runs terribly. I have to run the tractor with the choke half on. If I shut the choke off it sputters and backfires I have cleaned the carb 3 times. New points. Weird thing is that it runs fine if I pull off one spark plug wire. Messed with the timing and still nothing. Any Ideas?
 

Cleaning a two cylinder carb requires about 1/2 a day to access at least two hidden drilled passages and six almost invisible orifices.
A dunk in a tank of solvent and a hiss with the air hose will just cause frustration.
On the topic of spark. If the wires are not solid and the plugs are not non resistor Autolite 3116. Sooner or later there will be weak spark due to high resistance.
 
so you are trying to tell me that a 2cyl JD will run fine firing on only one? What is your definition of "fine". Your idle passages are plugged. Also check for cracked intake manifold. It runs on the idle passages even at wot sitting still(fast idle). Since yours are plugged it runs lean (pop/backfire) unless you close choke which will cause it to pull off the load nozzles which will load it up and foul the plugs. Still, it's hard to diagnose a two cylinder engine that runs fine on one cylinder.
 
Condenser. The muffler on my 630 is a little fat in the middle from a condenser caused backfire. Pulling the choke helps it run better because a weak spark won't fire a leaner mixture.
 
(quoted from post at 13:04:34 05/28/16)
Cleaning a two cylinder carb requires about 1/2 a day to access at least two hidden drilled passages and six almost invisible orifices.
A dunk in a tank of solvent and a hiss with the air hose will just cause frustration.
On the topic of spark. If the wires are not solid and the plugs are not non resistor Autolite 3116. Sooner or later there will be weak spark due to high resistance.
So how do i go about cleaning the carb if the solvent is cause for frustration. I have sprayed carb cleaner in what i thought was all the passages. Lol.
 
(quoted from post at 23:45:43 05/28/16)
(quoted from post at 13:04:34 05/28/16)
Cleaning a two cylinder carb requires about 1/2 a day to access at least two hidden drilled passages and six almost invisible orifices.
A dunk in a tank of solvent and a hiss with the air hose will just cause frustration.
On the topic of spark. If the wires are not solid and the plugs are not non resistor Autolite 3116. Sooner or later there will be weak spark due to high resistance.
So how do i go about cleaning the carb if the solvent is cause for frustration. I have sprayed carb cleaner in what i thought was all the passages. Lol.

Soaking in solvent and hissing with air will not clear the blocked passages. The carb has to be fully dismantled and the passages/orifices rodded out.
There are a couple of excellent shops with short turn around time that will clean,rebuild and test the carb.
 

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