# Help, 92 GT6000 giving me trouble In a bit of a time crunch



## guy45 (Sep 9, 2013)

Hey everybody,

I am new here and to mowers. I am visiting my grand parents and when I went to mow the lawn the mower ran like crap. I am trying to get this sorted out before I head back across the country on Sat. 

It's a 92 GT6000 with the 18hp kohler flat 2. 

Symptoms are as follows:
-Sounds like it is missing and surges at high and low throttle
-barley idles and will die at low throttle
-when throttling up or down it sputters and falls on its face
-backfires periodically 
-backfires like crazy under load (when I engage the blades)
-almost dies under load (when I let off the brake to start moving or when I furn sharply)

My grandfather told me a sears tech came out and looked at it. He thought it was the neutral safety switch or one that is pressed when you hold down the brake to start it. We have two replacements and neither of them changed anything.

The tech was nice enough to give him some spare parts which I put on.

Everything I have done:
-new fuel pump
-some new lines (still need to replace the big one from tank to filter)
-new carb
-fuel filter
-new plugs

I have checked the air filter and it is fine. It runs the same with or without it.

I used the manual to setup the carb according to specs. It is still running how it did before pretty much. 

The only other parts that I need at the moment are the intake manifold gaskets which I had to re-use because they were the only ones I did not have replacements for. 

If you guys have any input or ideas that would be great. 

I am not sure if this has a coil? or if it is maybe a bad ignition controller? I'll be scouring the manual after dinner tonight. 

thanks in advance!

Corey


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## Bill Kapaun (May 8, 2007)

Look under the seat for the Sears 917.xxxxxx number and post it.
There are models using the Kohler Magnum horizontal & vertical engines.
Let's pin down the correct one.


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## Argee (Sep 17, 2003)

Do you have fresh fuel in it?


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## guy45 (Sep 9, 2013)

Sorry it is horizontal. I just read he manual cover to cover. The model # is 917.255950. 

The gas is fresh, it still smells good and I know its always treated with sta-bil. 

From what I can see in the manual it may be the voltage regulator for the ignition or possibly the coil could be suspect?

The parts I am talking about are v-reg 25-755-03 and ign module 52-584-02.

thoughts? possibly timing off? or bad plug wires?


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## Bill Kapaun (May 8, 2007)

Not sure why you would think a voltage regulator would have anything to do with it???
The engine does not require 12V to run.
Just for starting, lights, battery charging and electric PTO.
Otherwise, it runs just like the one on your walk behind mower.

I'd temporarily disconnect the Operator Presence Relay.
IF the engine runs better, then there is a safety switch/wiring issue.
IF NOT, I'd look elsewhere.

Namely-
1. Drain the carb bowl. I know, the fuel's fresh. Maybe it is along with a slug of water in the bowl bottom.
If you know the fuel was treated with Stabil, how long ago? Ethanol still absorbs moisture.
I'd drain the fuel, put it in the car and get NEW gasoline.
2. check compression on both cylinders and compare the 2. Are they similar to each other and somewhat reasonable?


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## guy45 (Sep 9, 2013)

That makes sense, I was just shelling out ideas. I am still learning this as I go. 

That one also ran through my mind. I will tr that first. If the switch is the problem could I just by-pass it?

Where else do you suggest I look if it the switch isn't the problem?

Seeing as I have new fuel line to put on I wouldn't hurt to drain the gas. My grandpa says it is not even a month old. 

I'll have to rent a compression gauge tomorrow. What kind of numbers can I expect if the compression is healthy?


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## crown_pinion (Sep 10, 2013)

I had a Kawasaki engine doing a simular thing this year. Turned out to be a faulty coil. You might want to have it running and then pull off a plug wire. First one side and then the other. If it makes no difference then your coil is bad.


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## Bill Kapaun (May 8, 2007)

Don't get too fixated on absolute compression numbers.
We're basically looking for one that is noticeably low.
IF they're 60 or better, the engine should run fine. Probably even a little lower than that, once it starts.


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## guy45 (Sep 9, 2013)

crown_pinion said:


> I had a Kawasaki engine doing a simular thing this year. Turned out to be a faulty coil. You might want to have it running and then pull off a plug wire. First one side and then the other. If it makes no difference then your coil is bad.


Good to know, I will try this as well. 



Bill Kapaun said:


> Don't get too fixated on absolute compression numbers.
> We're basically looking for one that is noticeably low.
> IF they're 60 or better, the engine should run fine. Probably even a little lower than that, once it starts.


Ahh I see. I'll give that a whirl if the other tests come up negative. 

Thanks guys I will report back tomorrow!


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## wjjones (May 28, 2010)

guy45 said:


> Hey everybody,
> 
> I am new here and to mowers. I am visiting my grand parents and when I went to mow the lawn the mower ran like crap. I am trying to get this sorted out before I head back across the country on Sat.
> 
> ...




As mentioned try testing the coils, and check to make sure the fuel cap is not gummed up. Fuel vapor will clog it just like stale fuel does in the carb the best way to test it is to start the engine, and as soon as it starts to act up loosen the fuel cap to see if it smoothes out.


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## guy45 (Sep 9, 2013)

Alright due to bad weather yesterday in Mass I didn't go any further. 

I just did some tests and here is what I found.

1. started it up for the day- ran fine for 5-10 sec and began sputtering so I unplugged the sensor under the seat. nothing changed.

2. I unscrewed the gas cap and nothing changed. I left it off anyway. 

3. I unplugged one cylinder's plug wire and it almost died. same with the other side. So that rules out the coil. 

Not sure where to go from here?

I have yet to do a compression test so that will be next on the list


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## Bill Kapaun (May 8, 2007)

DID you unplug the OPR to see if that had any effect?
That was my FIRST suggestion. It eliminates/pinpoints several other items.


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## guy45 (Sep 9, 2013)

No I don't think so. What is OPR again?

I just ran a compression test left side by second crank went to 60ish then 75 on third. Same thing with the right side.

Not sure if I am reading it wrong but on the first stroke on both sides it would hit 25 or so.


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## guy45 (Sep 9, 2013)

Operator Presence relay, yes that was my first test today.

No change.

Should I leave it disconnected?


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## Bill Kapaun (May 8, 2007)

Compression sounds adequate.
You have to let it crank over a few more turns with the throttle open.
Kind of like pumping up a tire. You don't get it filled with just a couple pumps-

Download this manual, since it has the identical engine-
http://www.managemyhome.com/mmh/lis_pdf/OWNM/L0807534.pdf

Go to page 25 of 28.
Try turning the "main adjusting needle" some.
Nominal adjustment is around 1-1/2 to 2 turns out.


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## guy45 (Sep 9, 2013)

Well I tried making it a little richer and tune it in a bit. Then put the air cleaner on and went to drive it. It's backfiring still and sputtering and has even sputtered out a few times now.

I am totally stumped.


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## Bill Kapaun (May 8, 2007)

Try a little leaner


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## guy45 (Sep 9, 2013)

I leaned it out a bit but I cant get it to stop sputtering and surging. I am pretty well stumped on this. 

My grandparents are about ready to just have it taken away and buy a new one. I don't want them to go spend a ton of money on a brand new mower.

any other ideas?


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## Bill Kapaun (May 8, 2007)

Starting to get a bit desperate now...

Are you getting black smoke? Maybe the carb needle/seat isn't sealing properly, allowing an abnormally high fuel level in the bowl?
Grab a rag and a vise grip pliers and pinch off the fuel line while running.
Does it suddenly run much better shortly before it runs out of fuel & dies?

Run it in the dark and see if you can observe the spark plug wires flashing over to metal.


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## guy45 (Sep 9, 2013)

Ya it smokes a little on start up and a little puff here and there when it surges.

Stopped by a Sears earlier and those mowers looked like they were about ready to fall apart. Looks like total junk.

I didn't see any arching anywhere.

If I can't get it working tomorrow morning I am going to have a shop down the street pick it up and take a look. 

After seeing the new mowers I think my gamps wants to fix the one hes got.


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## square cratsman (Dec 19, 2018)

guy45 did you find the problem?


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## wjjones (May 28, 2010)

I dont think he came back I noticed the thread is from 2013.


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