Lawn Mower Repair

[deduncan]

Last week I was mowing the lawn, I ran out of gas, refilled, and began mowing again. About 2 minutes after I refilled, I ran over a patch of longer grass. The grass is nothing that the mower hasn't done before (probably 6-7" long), in fact it's done much longer grass and done just fine (this is a commercial mower). After I ran through the grass, it ran normally for another 15-20 seconds, then throttle started hesitating back and forth on it's own. When I try to engage the blade, it dies.

 

I let it sit for about 2 hours in the shade to let it cool down, thinking it was a heat issue. Every time it starts, it still throttles up and down on it's own, and when I engage the blade, it dies. I would take it to a lawnmower repair shop, but I'm extremely particular because I spent $800 on this mower. The only shop I really trust is backed up 2 weeks.

 

Do any of you have any ideas? Here is the mower I have for reference: John Deere JX75

 

Thanks!

[Wingnut]

I would say that you have something intermittently blocking your fuel flow.

 

Maybe you got bad gas, or something got into the carb, and is clogging it.

 

 

What's the plug look like?

[deduncan]

I replace the plug every 50 hours. It currently has about 7 hours on it. Good input on the fuel flow, I'll take a look in the tank/at the carb tonight. Hopefully that's what's causing it. I might also get some new fuel to rule that out as well.

[ness5575]

maybe a faulty safety switch? i know that mine (not a john deere, some cheap off brand that the old owners of the house threw in) will die completly if i put it in reverse with the blade going or if i get off the seat with the blade going.

maybe one of those "switches" is bad?

doesnt solve the weird idle problem, but just a thought...

[benis]

we actually had the same problem w/ a Cushman work cart at my job just a couple days ago. it seemed to be a problem w/ the engine actually getting the gas. every time we put the clutch in or laid off the hand throttle it would die. different machine, sound like pretty much the same prob.

we just started and stopped it a few times, fiddled w/ the throttle for quite a while, drove it at full speed for a bit, and eventually it just worked itself out. this was after it had run completely dry.

i know that doesnt help much, but the point is, we didnt have to take anything apart to fix it. just ran the machine for a while.

[Black02Silverado]

Sounds like running out of gas allowed junk from the bottom of the fuel tank to get into the carb. Check your inline fuel filter.

 

Changing out the spark plug is cheap and easy. I had problems with my 65 Impala, turns out that spark plugs were bad and I had just put them in only 1000 miles before my problems.

 

Never hurts to start with the cheapest easiest step and go from there.

[mka18]

A friend of mine just had something like this happen to his John Deere with a Kawasaki engine. It would throttle up and down all buy itself after he put new gas in it. He put premium in there thinking it would be better for the old mower. Reading some tractor message boards he found that the Kawasaki engines don’t like premium fuel for some reason. So, after draining it out and putting the regular octane fuel in there it runs like a champ again . Just might be something to try before you take it somewhere to get fixed.

 

Matt

[snoman]

My old JD 318 has done that a few times and when it has it has been a clogged low speed jet. The low speed jet carries engine at part throttle and the engine cycles in speed as it come on and off the main jet to get fuel that low speed circuit is not providing. The way I "cure" mine is to take off air cleaner and take engine to normal cutting speed and seal off carb intake with hand until it nearly dies (it will suck pretty hard) I do this a few times and all is back to normal. It is not very scientific but it does clear the jet.

[5.3LSilverado01]

Could be water in the gas. If your carb has a drain at the bottom of it, open it a bit and see is water comes out. Since water is heavier than gas, it will be at the bottom of the carb. This happened to my honda mower.

[snoman]

Could be water in the gas. If your carb has a drain at the bottom of it, open it a bit and see is water comes out. Since water is heavier than gas, it will be at the bottom of the carb. This happened to my honda mower.

THis is most likely true, my "crude" method sucked everything out of the bowl and straightened it right out. Water also does not pass through jets as well as gas does and can be a bit tuff to clear sometimes in small carbs.

[deduncan]

Well, I got it fixed. Not sure exactly what I did LOL. I took off the fuel lines and sucked all the fuel out of the tank. Cleaned it as best I could, put it back together, and now it works fine. Same gas and everything. I'm thinking there may have been something blocking the line and when I disconnected everything, it knocked it loose. Hopefully it stays fixed. Thanks for your help, y'all!