# Craftsman GT6000 Running rough, dies when engaging blades



## TEDious

I just aquired my grandpa's 1994 Craftsman GT6000 with the Kohler 20hp engine and a 48" deck, It has the electric lift for the mower deck and a plow blade.


I got it to run last week, ran strong, mowed with it, everything seemed to be fine, i een brush hogged a little over some water (2" deep) with some 8" grass, set the deck at full height and made a couple passes....

Now after a week of storage in a damp shed.... I couldnt hardly get it to start and when i finally have got it running, it is running somewhat smooth with some misses but it falls on its face when you full throttle and when engaging the electric PTO it kills the engine, the moment i disengage, the engine continues to fire?! Almost like the pto is like a kill switch...

I'm lost, please help... I replaced the fuel filter, the plugs look alright, but spark looks kinda weak. Maybe a fuel pump? or Ignition module?

Thanks ahead for any help, 11 inches of rain in two months here in michigan is like a monsoon... i have over an acre that is looking pretty scary if i cant get this Machine running soon.


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## TEDious

di do de do di do di............ it's like jeopardy... forum not so busy, eh?

Well, with some trouble shooting, if i hotwire the PTO, the deck engages and all is well....

Oh yeah, and a couple new plugs, it is running better.

So , now to figure out what connection is killing it?........


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## wjjones

TEDious said:


> di do de do di do di............ it's like jeopardy... forum not so busy, eh?
> 
> Well, with some trouble shooting, if i hotwire the PTO, the deck engages and all is well....
> 
> Oh yeah, and a couple new plugs, it is running better.
> 
> So , now to figure out what connection is killing it?........


 Welcome to the Forum!..TEDious..
Is there any chance the water got into the fuel, or water in your fuel can?? The only other thing i can think of is the fuel filter, and air filter may need changing. I am sure some other members will weigh in on this problem shortly.


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## dangeroustoys56

Sounds sorta like the GT6000 i have - mine has a 20HP onan tho, with the electric deck lift and all the bells, whistles and fancy lights on the dash.

Stock wiring harness's use a relay for the deck clutch ( under the hood) - id try to replace that one first ( on my other GTII I just ran a whole new separate deck PTO harness direct to the battery - with switch on dash - and ran a 20amp inline fuse - works good ) - also check and make sure the battery is big enough to handle all that - mine actually had a tag on the positive cable that said 'minumum 600 CCA battery required '

If it still acts up- change the PTO switch - if it still acts up after that ..... probably time for a new PTO clutch, i checked to see what they run - about $400.


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## TEDious

HA! If i unplug the relay everything works.

I have a new fuel filter, plugs, no air filter at the moment

gas line antifreeze and some stabil

Starts and ran pretty good, Mowed about 400ft... then it started dying. running bad at full throttle, lower it a little, runs better but then cant mow and it starts bogging.

I took the carb off last night, cleaned everything i could without removing the little freeze plugs, reinstalled it at 9:30 last night.

Gonna have to try it today after work. (at least it's pretty much stopped raining here)

May have to mow this time with my old 5hp Firestone.......


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## TEDious

There was some old gas in the tank when i filled it up, chance that is causing problems?

I added about half a tank of new gas, gasline antifreeze and some stabil yesterday.


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## dangeroustoys56

Probably shouldve dumped the old stale gas- used to be you could use it for at least a year - now with ethanol blended in- it isnt lasting a couple months - id drain it totally and put fresh in - you might want to flush the tank out - i know when i went thru my old 86 GTII i totally took it apart, and first on my list when it went back together was a whole new gas line to the tank ( a serious pain because its such a long line) . 

Eventually you might want to put a carb kit in it - specially if its never been rebuilt - i have a 99 murray hydro with a 17HP twin briggs - ran horrible and coughed sputtered - i put a $20 carb kit in it ( all new gaskets and stuff to rebuild fuel pump) and it runs awsome now - once i fit a deck to it, itll be ready for mowing.


I mentioned the relay because i had some EFI issues with my old 89 F150 years ago - because of some bad wiring, i kept popping relays under the hood - those were like $20 each tho. An autoparts store should be able to hook you up with a new relay.


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## TEDious

Update: I took out the fuel lines, drained the gas, replaced the lines and the filter, opened the fuel pump (clean)

got it started, mowed at 60% throttle for 15 mins until it died again

If i throttle up it wants to stumble, backfire, die..... i also needed a touch of choke to keep i there.

It sounded like it would build more speed and power for a couple secs when the deck would load up with taller grass....

Then i broke the insulator off the rt side plug checking to see if i flooded it. Left it there, 150ft back from the house in the rough. Gonna play it where it lays....

by the time i'm done, whole damn machine gonna be rebuilt......

fuel pump, ignition module? Fuel pump is nylon bodied non-servicable, can get a new one tues i think, maybe sooner


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## HickoryNut

Hey, just a thought, did you hit anything or stall out in the brush and water? Could it be the flywheel key??? Strting to sound like a timing iisue IMHO


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## jhngardner367

If it has a solenoid,on the bottom of the carb,check the wire to it.Also check to see if the main jet isn't plugged.If you have some clear fuel line.put some between the filter,and the carb,run the tractor,and watch the fuel flow.This will let you see if it's the fuel pump,or,if you see separation,or dirt,if it's a bad filter.


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## wjjones

HickoryNut said:


> Hey, just a thought, did you hit anything or stall out in the brush and water? Could it be the flywheel key??? Strting to sound like a timing iisue IMHO



Or maybe a coil heating up cutting out... Just another idea?


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## TEDious

ok..... bit the bullet, bought the fuel pump..... minor improvement. Won't run full throttle, or even above 4th gear while mowing.... falls on its face. Needs some choke to stay running smooth....

Gonna get the number off the engine and see if i can get a rebuild kit for the carb tomorrow....

Hoping its not the ignition module... $$$, Guess i could check comression too.

Wasn't brush, just tall grass, and the deck was never in the water. Dont have a solenoid on the carb, just fuel in, idle needle, and high speed needle


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## TEDious

and, if it matters, it will not run if i pull either plug wire, it dies when running on one.


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## Mickey

TEDious said:


> and, if it matters, it will not run if i pull either plug wire, it dies when running on one.


This is normal. Like most twins that don't have a dist, both plugs are on the same circuit so to speak. Can be thought as as one plug is the positive and the other is the negative side of the circuit.

Both plugs fire at same time so any ign problems affects both cyl.


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## TEDious

BTW, Horizontal shaft, everything is belt driven.

I think i'm going to try a carb kit today...... if this doesnt do it... i swear i'm going to go get that 8hp wards.....


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## wjjones

TEDious said:


> BTW, Horizontal shaft, everything is belt driven.
> 
> I think i'm going to try a carb kit today...... if this doesnt do it... i swear i'm going to go get that 8hp wards.....



It does sound like a dirty carb, or it needs an overhaul... Is there a breather vent tube on yours?


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## TEDious

It's soaking in a gallon of berrymans chem-tool right now......


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## wjjones

TEDious said:


> It's soaking in a gallon of berrymans chem-tool right now......



Let us know how the rebuild, or cleaning works out...


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## TEDious

i'm about to give up..... after the cleaning and new gaskets, ran better than ever for about 5-10 mins. Now back to $hit.

about to go to the curb for the $$ i've got into it.


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## TEDious

Ok.... Now it will run for about 10-15 mins, mowing pretty strong, no choke, seemingly no misfires.... then all of the sudden, back to no good again. I left it for 30-40 mins, same thing. What is the deal? Soak the carb again? remove welch plugs and do it all? Or is this indicative of ignition?


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## wjjones

TEDious said:


> Ok.... Now it will run for about 10-15 mins, mowing pretty strong, no choke, seemingly no misfires.... then all of the sudden, back to no good again. I left it for 30-40 mins, same thing. What is the deal? Soak the carb again? remove welch plugs and do it all? Or is this indicative of ignition?



My neighbor had this similar problem, and it was the coil heating up, and either killing the engine , or running rough.. When it dies like this do you have any way to check for spark at the plug wires?


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## Wishbonez51

I have built many small engines and I can say with pretty much certanty it is your coil. You let the tractor sit till the engine is cool to the touch. I bet the tractor will fire right up and run with no problem, that is untill the coil gets hot again. Good luck and report back. Oh and dont give up, mechanical problems is apart of all the fun. Besides you could buy a brand new one and have problems. Stick with it and you will get it run great in no time.


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## TEDious

Yeah.... Going to get the Ignition Module today, $98

Better be it


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## TEDious

Viola! After an extensive dis-assembly and re-assembly... and some cleaning.

I was able to mow at full throttle, in 6th gear, Wa-hoo!


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## Wishbonez51

TEDious said:


> Viola! After an extensive dis-assembly and re-assembly... and some cleaning.
> 
> I was able to mow at full throttle, in 6th gear, Wa-hoo!


Now see thats what I am talking about. All of that frustration and sweat paid off.
Glad to see you back out n the lawn. :tractorsm


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## jhngardner367

Replace the regulator/rectifier unit.It's not putting out enough to give spark for the engine,and the pto,too.you may also have to replace the ignition coil,if the spark doesn't get stronger.By the way,check the plug gap,first..it should be .030,for flatheads,and .035 for overhead valve engines.Flat head engines will use a j19lm plug,and ohv's will use an rv17yc (in champion).


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## wjjones

TEDious said:


> Viola! After an extensive dis-assembly and re-assembly... and some cleaning.
> 
> I was able to mow at full throttle, in 6th gear, Wa-hoo!



Glad to hear you got it going..


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## dangeroustoys56

Im still thinking its fuel related - try 'testing' the fuel pump - remove the fuel line after the pump and put it in a jar/jug ( where it wont splash) and try cranking it over, seeing how much fuel comes out - the fuel line might be degrading , causing the slow fuel flow or a chunk of crud is plugging the line in the tank.


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## TEDious

jhngardner367 and dangeroustoys56...... read the thread, problem solved. Thanks again.


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