Adjusting a John Deere GX75


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Old 05-23-16, 10:28 AM
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Adjusting a John Deere GX75

Purchased this GX75 riding mower, used, and need to make an adjustment to settle down the engine.

I'm getting a hunting (revving up and down) at all settings of the throttle. I know there is no air/fuel adjustment for the main jet, which makes no sense at all. I have already cleaned the carb but I'm not sure this is carb-related. The rev swings are just wide and erratic.

Can someone give me the procedure for adjusting the governor static arm on this machine, please, so I can see of that helps.

If you feel it is the carb, would installing a smaller main jet help. What else would wear other than that?
 
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Old 05-23-16, 10:37 AM
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How did you clean the carburetor? Did you remove and disassemble it?
 
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Old 05-23-16, 11:05 AM
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Yes. All but the two inner fluted tubes. The slots were a bit damaged and did not want to run the risk of stripping completely.

A few videos I've seen suggest actually going wider on the main jet to remedy surging. That the engine is not getting enough gas rather than too much from a worn main jet. The plug was a bit white so perhaps that is the issue. Running a drill through the main jet to open it up but then no turning back : (

Not having a way to adjust makes this a crap shoot.
 
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Old 05-23-16, 11:49 AM
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Something is still clogged in the carb. Did you remove the tiny jet from the top side of the carb? That one often gets missed and is often the problem. The carb was jetted properly from the factory, no reason the jets would suddenly be too small now. Once you get it cleaned right, it will run right. If you drill it you will probably never get it just right and then when the clog comes out it will be flooding and you'll be looking for a $150-$200 carburetor.
 
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Old 05-23-16, 11:58 AM
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You mean the idle jet? I did but perhaps it got re-clogged. I will take another look-see.
 

Last edited by outdoormike; 05-23-16 at 12:17 PM.
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Old 05-23-16, 05:26 PM
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Yes. It has a very very tiny hole in the very end that is very often clogged. It affects the engine at all rpm when it's clogged.
 
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Old 05-23-16, 10:28 PM
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What engine do you have that mower ??

A 290 Kawi or a Briggs or A kholer ???
 
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Old 05-24-16, 02:28 AM
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Kawasaki on this one.
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