LX277 Won't run at full Throttle

prowler

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I've got a air cooled, Kawasaki FH500V, 494cc, 17HP VTwin OHV LX277.

Since last year, I've been fighting this machine as it stumbles and surges. After a few posts on this forum back then, I changed out most items usually suggested on this forum regarding "surging" problems at one time or another ... and even had some temporary relief - but always returns back to its erratic behavior. (replaced fuel pump, fuel lines, solenoid - pulled gas tank to check for obstructions) I'm convinced this is an air/fuel issue since choking the machine usually smooths out the engine at lower throttle.

I used this machine this year so far,usually being able to run at half throttle. However, running at half throttle does not allow for the best mowing job.

Question: What should I look for now when I sense this problem really takes hold whenever the mower gets hot. In other words, I use it for a half hour or so, but then it starts acting up and then gets to a point where "choking" it barely gets me back to the shed.

Advice welcome. Thanks.
 

pile81

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Fill your fuel tank up to the top, run it, when it starts acting up unscrew the fuel cap and see if it straightens up.......just to rule out the simplest thing it could be....
 

prowler

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Fill your fuel tank up to the top, run it, when it starts acting up unscrew the fuel cap and see if it straightens up.......just to rule out the simplest thing it could be....

Anything is worth a try. Thanks. I've pretty much ruled out the fuel cap - even added my own vent hole.
 

pile81

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If it was coils which is a similar symptom choking it wouldn't really male a difference cause no matter how much fuel you dump in the cylinder without spark it isn't gonna do much....if you made your own vent hole that takes care of the cap......hmmmm let me ponder it and see if anything pops into mind the next day or 2
 

BBO

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I (replaced fuel pump, fuel lines, solenoid - pulled gas tank to check for obstructions) I'm convinced this is an air/fuel issue.

How old is the machine and have you rebuilt the carburetor?
 

prowler

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....if you made your own vent hole that takes care of the cap......hmmmm let me ponder it and see if anything pops into mind the next day or 2

Question: Does the gas tank do anything other than serve as a container for the fuel? Could an issue with the gas tank (which is a pain to remove and inspect) be removed from the equation here [bypassing the actual gas tank] by running a hose from the input of the fuel pump to a gallon jug full of gas?

Fuel Tank.JPG
 

prowler

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How old is the machine and have you rebuilt the carburetor?

This machine is 13 years old.

I have never actually 'rebuilt' the carburetor, but regarding this specific problem which began one year ago, it has been to the John Deere shop twice where the tech inspected and cleaned the carburetor - and I have cleaned it myself a couple of times. If this problem could eventually be isolated to the carburetor I would gladly pay the $200 to buy a new one rather than continue on taking things apart on this machine.

Turning back the clock when I paid the big bucks for the solenoid, I should have replaced the carburetor.
 

prowler

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This machine is 13 years old.

Always open for new ideas here. The basic "fixes" have mostly all be tried during the past several months but every time somebody posts something it helps my thought process.

This AM, I started the LX277 cold and it ran full throttle for approx 5 minutes, enough time to mow 100 feet. Then it started sputtering and I was able to choke it so it ran full throttle back to where I started. Then, it would only run half throttle while being choked.

Where does "heat" compromise the air/fuel mix? The "choke" thingy makes me believe too much air is entering the carburetor somewhere after it runs several minutes.

Thanks.
 

prowler

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Always open for new ideas here.

Just as we have done all Spring long, we mowed approx 2 acres today with this mower running at half throttle. Doesn't do such a hot job of mowing, but at least the majority of it gets cut down. After each mowing, we take out the sweeper and re-travel most of the yard we just mowed in order to pick up the grass that wasn't properly cut and discharged.
 

pile81

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Yeah u can bypass the tank and hook a remote tank to it to see if possibly the pick up tube is partially clogged or something.....what u can also try is just pulling the bowl off and crank to see if the inlet is lettin fuel flow thru good, I've seen insects and plant matter plug fuel line and cause similar problems......
 
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